Jerzy Janowicz is a fearless risk-taker on the court who could end Andy Murray's Wimbledon dream today if he rises to the occasion on Centre Court.
At six foot eight he can hit aces all day and he has a thunderous forehand to match, but he also moves really well for a big guy and has great touch too.
His forehand is 'old school', which I like; he strikes the ball flat and can hit through the court.
When Rafael Nadal and Roger Federer went out of the Championships I felt Janowicz was the chief threat to Andy's title hopes (in that half of the draw) and now I can't wait to see how he will handle the pressure-cooker atmosphere of a Centre Court semi-final.
Andy, of course, has experience on his side and will have a genuine edge if this becomes a physical battle.
If Andy plays as far back behind the baseline as he did against Verdasco, then I think he'll struggle to win because Janowicz is a better player than Verdasco.
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He didn't play well against Fernando Verdasco on Wednesday - the second set was particularly poor - but he was able to show the courage and will to win that we've come to expect from him.
Sometimes it is good to be tested and Verdasco certainly put him through the ringer. At times the Spaniard was hitting second serves of 120mph and Murray can expect plenty more of that today.
I think Murray needs to come out and use his big-match experience to take the match to Janowicz.
There might be one point in the first three or four games where he can rock the Pole's confidence and belief and it's crucial that he takes it.
But if Andy plays as far back behind the baseline as he did against Verdasco, then I think he'll struggle to win because Janowicz is a better grasscourt player than Verdasco.
With that in mind I genuinely feel that the fans have a massive role to play; they were very quiet - surprisingly so - when things went against Andy on Wednesday.
At that point Andy really needed to have the fans with him and a few fist-pumps might have helped stir them into action. We know fans will respond to great play but in an ideal world you want Murray and the fans to galvanise each other.
The first semi-final of the day between Novak Djokovic and Juan Martin del Potro should also be a hard-hitting affair.
Everything points towards a win for the Serb - after all, he's World No 1, he's seeded No 1 and he's playing great and hasn't dropped a set.
Moreover Del Potro is carrying a knee injury and, to all intents and purposes, has almost been out of the tournament on two occasions.
He wasn't sure if he was going to play his last 16 match against Andreas Seppi, or if he would complete his quarter-final match against David Ferrer.
However, there's something about Del Potro: when he relaxes and hits the ball to the best of his ability he is devastating. He's served well throughout the tournament and his forehand remains mightily impressive.
And don't forget that the last time they met at Wimbledon, at last year's Olympics, an injured Del Potro won!
So the way this Wimbledon has gone something tells me that this match isn't a foregone conclusion. Expect a few twists along the way!