Last Updated: 04/07/14 10:57pm
That's all for this commentary for tonight. Stick around for a full match report and more - and join us again on Saturday for coverage of Argentina v Belgium and Holland v Costa Rica.
Full-time in Fortaleza: Brazil 2 (Thiago Silva 7, David Luiz 68) Colombia 1 (James Rodriguez pen 80). Brazil will play Germany in the first semi-final in Belo Horizonte on Tuesday.
Marcelo boots the ball away for a corner as Colombia threaten again. Ramos flicks a header across goal, but wide of the far post.
Great play from Rodriguez but the ball doesn't quite run for Ramos in the area and Brazil can clear.
Third and final Brazil change - Henrique ON, Neymar OFF. Neymar leaves the pitch on a stretcher (88).
Quintero's corner is sent dangerously in to the near post, Fred puts it behind. The next one goes for a throw as Ramires clears.
Rodriguez's run-up helps fool Julio Cesar, who goes left as the ball is slid to the other side of the Brazil goalkeeper. 2-1.
YELLOW CARD! Julio Cesar is booked for bringing down Bacca in the box after a great pass from James Rodriguez (77). David Luiz was back too, which might have prevented a red card. Cesar eventually clambers to his feet, having claimed an injury.
Yepes comes in with a crucial tackle to steal the ball off Neymar on the edge of the Colombia penalty area.
Colombia have every right to feel aggrieved. The Spanish referee let so many bad tackles go before electing to book Rodriguez who had tried to pull out of a challenge on Hulk. That was punished in some style by David Luiz, though.
YELLOW CARD! Colombia skipper Yepes is booked for dissent (72). Incredible atmosphere now that Brazil have a two-goal lead.
Second change for Colombia, who are fuming about the free-kick decision that led to the goal - Carlos Bacca ON, Teo Gutierrez OFF.
From the free-kick around 30 yards out, David Luiz takes a big run-up and then strikes a sensational shot, right-footed. The ball flies over the wall before dipping onto the fingertips of Ospina's outstretched left glove - but the Colombia goalkeeper can't keep it out.
YELLOW CARD! James Rodriguez collects Colombia's first booking (67) for bringing down Hulk on a slide tackle. Rather harsh - he's been on the receiving end of some over-zealous tackling from the hosts.
Colombia have the ball in the back of the net but the assistant referee had his flag up for offside from the initial free-kick. The ball hit David Luiz and fell for Yepes to tuck away - but it's disallowed, much to his displeasure.
YELLOW CARD! At last! Brazil skipper Thiago Silva is booked for impeding the kick of David Ospina (64). That means he will be suspended if the hosts reach the semi-final against Germany.
Cuadrado obstructs Neymar clumsily, but still no card from Senor Velasco Carballo. Getting silly now.
A volley attempt from the edge of the box from Guarin goes over, after he was teed up by James Rodriguez. Gutierrez didn't help with a poor ball back for Colombia.
Thiago Silva hurt himself in the process of fouling Ramos. The Spanish referee needs to get a grip on this game.
Lovely backheel flick from Cuadrado to Ramos running down the right. Doesn't quite come off, but Colombia stay on the attack and they may well need some trickery to get back on level terms here.
Brazil should have had a corner after Zapata rose above David Luiz to head away Neymar's free-kick, but it's missed by the officials.
Free-kick to Colombia from the right channel, 30 yards out. Thiago Silva heads away Cuadrado's delivery.
Our man in the Estadio Castelao tonight is Pete Hall aka @PeteHall86. Here's his half-time update: "What a game so far! The crowd here have not stopped. They actually look exhausted, fanning their faces, sitting back in their chairs trying to get ready for the second half. Without them, Brazil would not have been able to muster such intensity! James Rodriguez is getting booed every time he touches the ball. Immense pressure on such young shoulders."
A half-time update from Sky Bet: Brazil are now a very short 1/6 to win this one within 90 minutes. The draw is 9/2, while Colombia are long shots at 12/1.
Joe Wink-Simmonds emails in: "Looking at the feed, I do think Brazil have been the better side. However I do think that Colombia deserve a win today and should progress into the semi-finals. If Colombia make a strong substitution at half time, I think they can win. My prediction is 3-1 to Colombia."
Chris Green from Huddersfield emails in to say: "The hosts may be leading at the interval after dominating possession for the majority of the first period, but Colombia are by no means out of this. They need to keep believing in themselves because they are capable of turning this around."
Half-time in Fortaleza: Brazil 1 (Thiago Silva 7) Colombia 0. The hosts have been the better side and deservedly lead, in what has been an open, entertaining contest. Your thoughts? Email me at firstname.lastname@example.org or tweet me on @jonboy79.
Neymar goes for the top corner of Ospina's goal but curls it just a little too high and a little too wide.
Ibarbo goes down injured in the Brazil penalty area, but is soon up on his feet again. Really physical game out there.
Brazil charge down Rodriguez's free-kick, then the hosts give away another set-piece as Thiago Silva fouls Cuadrado wide left. Rodriguez sends the ball into the area where Julio Cesar claims it.
Colombia win a free-kick right on the edge of the area in a central position. Fernandinho adjudged to have gone in high on Ibarbo after Cuadrado had teed up Armero's left-wing cross.
Neymar releases Maicon into the area, and Ibarbo sprints back but gives away a corner. Fernandinho heads over from Neymar's set piece.
Brazil have had 57% possession so far. They lead Colombia on shots by eight (four on target) to three (zero on target).
An excellent save from Ospina to again deny Hulk, who tried a low hard shot from the left side of the area after Marcelo's pull-back. Yepes heads the ball away.
Hulk tries some trickery on the left flank and then finds Marcelo, whose shot deflects over the bar off the head of team-mate Fred.
Colombia losing their discipline as Fernandinho impedes James Rodriguez, and are almost punished as Ibarbo gets dispossessed. Paulinho is then stopped by the grounded Zapata inside the area.
Cuadrado is released in a three-on-one situation but wastes the opportunity from the right side of the Colombia attack. Poor decision making.
Colombia are straight up the other end and Fernandinho boots James Rodriguez's left-wing cross out for a throw.
Ospina saves from Hulk inside the area after good work by Neymar, and then from Oscar. Neymar's corner is headed away by Ibarbo.
Neymar takes Brazil's second corner, and it's headed away by Yepes but only to the edge of the area where Cuadrado loses the ball. Hulk takes it on and just about gets the ball across, but Colombia clear.
Very scrappy spell now. Lots of fouls and free-kicks being given. Cuadrado the latest to win one, off Marcelo.
Fernandinho comes in with an over-physical challenge on James Rodriguez. Free-kick to Colombia in the centre circle.
Cuadrado shoots low left footed from the edge of the box - into the side netting. A slight deflection means it's a corner, which Fernandinho heads away. Good response from Colombia.
That's got this Fortaleza stadium rocking. Will Brazil relax into this one now they are ahead so early? Colombia win a free-kick as Oscar fouls James Rodriguez 35 yards out.
Neymar's corner comes all the way over to the far post where Brazil captain Thiago Silva takes advantage of ball-watching from Carlos Sanchez and bundles the ball home from five yards. 1-0.
Fernandinho breaks up a Colombia attack after James Rodriguez found Gutierrez on the right. Then Fred wins a free-kick after a heavy Sanchez challenge.
Neymar's on the right, closely tracked by Sanchez, with Hulk on the left. Paulinho is looking to attack down the right flank too.
Three players on either side are riding bookings. Thiago Silva, Hulk and Neymar for Brazil, and Pablo Armero, Fredy Guarin and Carlos Sanchez for Colombia. Spaniard Carlos Velasco Carballo is the referee for this one.
One more Opta stat before we kick off... Colombia last beat Brazil at the Copa America in 1991, losing seven and drawing five since that encounter. That defeat remains Brazil's only competitive loss to Colombia, winning 13 of their competitive meetings (six games have been draws).
The singing of the national anthems has been extra special for both of these teams at the World Cup, particularly Brazil. First, both captains read a 'Say No' to racism and discrimination message, and that's being well received by the crowd.
A bit more from Sky Sports pundit Jamie Redknapp as the players emerge: "They are so evenly matched and there's not a great deal to choose between these two sides, but I'll say Brazil can go through with that little bit of extra quality and home advantage. The pressure they are being put under seems to be pushing them and driving them on even more so I am going for Brazil to qualify, but through extra-time."
The players are in the tunnel and will be on their way out onto the pitch shortly. Brazil are in yellow shirts with white shorts tonight, Colombia wearing their red away shirts with dark shorts.
Our man in Fortaleza, Pete Hall (follow him on Twitter at @PeteHall86), has been watching the players warm up. He writes: "James Rodriguez getting booed as his name is announced. Just the added inspiration he needed."
Brazil have conceded in each of their last eight World Cup quarter-finals, so 'both teams to score' could well be a good wager. That's one of Jamie Redknapp's Hot Tips for Sky Bet, at 11/10. He also fancies a 2-1 Brazil win at 17/2, and Neymar 1st goalscorer at 7/2.
Twitter time! Faisal Ahmed aka @fuzzyy99 tweets: "Under this immense pressure, I think Brazil will crumble. Going for a 2-1 Colombia win - Rodriguez (2) and Neymar (1) scoring!" As for @RimmerMarc, he sees a low-scoring tight affair in keeping with other recent games: "I reckon 1-0 Brazil, Fred to score."
We shouldn't talk about hotshot Rodriguez without also mentioning the supply route, Juan Cuadrado. He's the first player to provide four assists in a World Cup since Juan Roman Riquelme and Francesco Totti in 2006. Will he set up another goal for Colombia tonight?
More of your predictions now. On email, Jordan Green says: "James Rodriguez will run the show tonight, Colombia will win 2-1." Joe Clifford writes: "Colombia to win 2-0, they've got all the banter, James Rodriguez with the first and then a cheeky header from Gutierrez to finish Brazil off!"
This game puts five-goal top-scorer James Rodriguez of Colombia against four-goal Brazilian 'poster boy' Neymar. Rodriguez is looking to become the first player since Rivaldo in 2002 to score in the first five games of a World Cup.
It's an absolute sea of yellow inside the stadium in Fortaleza. Should be over 67,000 packed in to witness this one.
We want to see goals, but the recent history of this fixture is more than a little concerning. The last four games between Brazil and Colombia have ended in draws - with three of those finishing goalless.
Let's have a look at the betting, shall we? Brazil are 3/4 with Sky Bet to get this one wrapped up within 90 minutes. Those fancying Colombia can back them at a tasty 4/1, while the draw is 13/5.
Our pundit Paul Merson has given his prediction, and he's backing Brazil to win 2-1: "I think Brazil have been absolutely shocking and if they win the World Cup, then they will probably be the worst team to ever win it. Neymar is the stand-out player and if he doesn't turn up to the party, then you can't imagine Hulk doing anything for them. Or Fred. But the thing is, when you have got a record of playing 40-odd games at home without losing, then you're going to be hard to beat. I will go for Brazil because they're at home and the Colombians might end up playing against the shirt, rather than the players."
A load of you are backing Colombia to win on the emails tonight. Richard Williams says "You can't win a World Cup with Luiz, Paulinho and Fred in your side." Peter Barraclough writes: "3-1 Colombia, with my favourite player of the tournament scoring - Cuadrado!"
Our man Pete Hall is in the Estadio Castelao in Fortaleza tonight: "What an atmosphere outside the ground! All very amicable. For a change, Brazil fans will be up against it in trying to match the volume of the fervent Colombians. The hot, sticky weather has brought out all sorts of colourful attire, with photographers not knowing where to start! The hosts are all relying on that man Neymar to inspire them, while Los Cafeteros fancy their chances, and with star-man James Rodriguez in the form he is in, why not..."
Brazil have reached the quarter-finals in each of their last six World Cups, but they haven't gone further than this round since 2002. Colombia, on the other hand, have made the last eight for the first time in their World Cup history.
Daniel Madden is first on the emails, and is backing the hosts strongly: "I reckon 3-0 Brazil tonight with the Incredible Hulk banging in a spectacular hat-trick!"
We now know that the winner of this one will face Germany in the first semi-final in Belo Horizonte on Tuesday. Looking at the line-ups, who do you think will go through? Any predictions, let me know.
There are also two changes to Jose Pekerman's Colombia team that began the 2-0 win over Uruguay in the last 16. In come Fredy Guarin and Victor Ibarbo, with Jackson Martinez and Abel Aguilar on the bench.
Colombia team (4-4-2): Ospina; Zuniga, Zapata, Yepes (c), Armero; Cuadrado, Sanchez, Guarin, Rodriguez; Gutierrez, Ibarbo.
So Neymar is fit to start for Brazil, but Dani Alves is missing along with the banned Luiz Gustavo. Luiz Felipe Scolari therefore makes two changes from the team that began the round-of-16 win over Chile, with Maicon and Paulinho coming into the side.
Brazil team (4-2-3-1): Julio Cesar; Maicon, Thiago Silva (c), David Luiz, Marcelo; Fernandinho, Paulinho; Hulk, Oscar, Neymar; Fred.
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