Arsenal's Champions League hopes were dealt a crushing blow as Lionel Messi struck twice to hand Barcelona a 2-0 win in the first leg of their last-16 tie at the Emirates Stadium.
The Gunners defended doggedly and spurned a number of scoring chances before Messi finished off a blistering Barcelona counter-attack for the opening goal after 71 minutes.
He added his second from the penalty spot just 12 minutes later after Arsenal substitute Mathieu Flamini felled the Argentine with his first involvement in the game.
The result leaves Arsenal on the brink of their sixth last-16 elimination in a row. Here, our reporter at the Emirates reflects on the big talking points from the game.
Arsenal's gameplan frustrates Barcelona
"I cannot go into a game and think I will just play for a zero-zero. It's against my nature." Despite Arsene Wenger's comments in the build-up to this game, it was no great surprise to see the Arsenal manager set up his side to sit deep, contain Barcelona and play on the counter-attack.
For 71 minutes, the defensive gameplan worked. Arsenal had just 28 per cent of the possession in the first half but they worked tirelessly without the ball and restricted the space in and around their penalty box, with Barcelona's only clear chance of the half coming when Luis Suarez headed narrowly wide just before the break.
Petr Cech needed to be at his best to thwart Neymar early in the second period, but the Gunners continued to frustrate the visitors until a costly lapse of concentration saw them carved open on the break for the opener. Messi's second goal then undid all of their good work.
"They are better than us and everybody knows that but I believe we could have won the game tonight if we had kept the discipline until the end," said a frustrated Wenger, who saw similarities with last year's last-16 defeat. "Like against Monaco, it is exactly the same," he said. "We are caught in exactly the same way."
Gunners misfire in front of goal
Wenger has repeatedly called on his side to be more "efficient" in front of goal but their lack of composure cost them dearly yet again. Arsenal's profligacy has been a glaring issue throughout the campaign, and the manager spun away in anger as Alex Oxlade-Chamberlain shot weakly at Marc-Andre Ter Stegen from eight yards out in the 27th minute.
"We had an unbelievable chance in the first half," said Wenger. "The way we finished our chances was a problem today." Oxlade-Chamberlain was guilty of squandering a fantastic counter-attack with a clumsy touch not long afterwards, but he wasn't the only Arsenal player to fluff his lines.
Aaron Ramsey missed three presentable chances, and the hosts' struggles in front of goal were summed up by a moment shortly before Barcelona's second goal when Olivier Giroud inexplicably passed the ball into an empty space as a threatening Arsenal attack entered the Barcelona box.
Arsenal's lack of cutting edge contrasted sharply with the ruthlessness of Barcelona's brilliant opener. All three members of their hallowed front three were involved. First, Neymar flicked the ball to Suarez on the left wing, who returned it through Koscielny's legs and the Brazil international then squared to Messi in the box.
The Argentine hadn't scored in his previous six games against Petr Cech, but his composure was remarkable, delaying his shot and deceiving the former Chelsea goalkeeper before dispatching the finish. Suarez hit the post when he probably should have added a third, but by that point MSN had already done enough to all but end the tie.
Messi's brace took the trio's total to 93 for the season in all competitions, and there's still three months of the season to go.
No happy reunion for Sanchez
In the formation of Barcelona's MSN, Alexis Sanchez was the casualty, with his £30m transfer to Arsenal coming shortly before Suarez's arrival from Liverpool in the summer of 2014. A reunion with his former club gave the Chilean a chance to prove a point, but he was unable to come up with a decisive contribution.
Sanchez was typically industrious and energetic without the ball, but his recent struggle for form continued. The 27-year-old's evening was made especially difficult by a brilliant performance from Barcelona right-back Dani Alves, but by repeatedly losing possession he invited more pressure on his side at crucial moments.
The statistics showed he won plenty of duels and tackles and ranked second for interceptions, but on a night when Arsenal needed more from their attacking players at the other end, he rarely threatened to make a breakthrough.
Flamini's nightmare cameo
Wenger's decision to replace Francis Coquelin with Mathieu Flamini when Arsenal were chasing an equaliser felt like a strange one, and it had disastrous consequences as, just 47 seconds after coming on, the Frenchman's clumsy foul handed Barcelona their penalty to effectively kill the tie.It provoked a furious reaction from Arsenal supporters inside the Emirates Stadium, and as he finished the game having touched the ball just three times in seven minutes, it was fair to wonder why Wenger had bothered.