I think Rafael Nadal is improving every time he engages in battle. He may also be improving in practice but he is certainly doing it when he plays his matches. For Rafael Nadal and Roger Federer, the tournament really starts in the quarter-finals at the Grand Slams.

The second week for someone like Carlos Moya is heavy, because he has played a lot of tough matches, but for guys like Nadal and Federer they seem to be getting fresher, fitter and stronger.

I think it's funny because Moya and Nadal have been practising together for five or six years, and even though he is the less experienced player it seem that Nadal knows more about Moya's game than Moya does about Nadal. Of course Nadal is ranked number two in the world while Moya is climbing his way back up the rankings, but I have to say it was quite an interesting contrast.

Nadal has heavy, heavy, heavy topspin on his forehand and he can also put sidespin on the ball as well. He can hit it inside-out, where the ball moves from right to left for the left-hander, or he can hook it.

Moya doesn't quite hit it with as much topspin. It's a little flatter and definitely favours the inside-out forehand. Both men have very extreme grips. If you showed me that 20 years ago I would say you were crazy, you can't hit a tennis ball like that!

Nadal plays like Moya in many ways but he has developed an all-court game that people don't expect of him. He's just a great player and will be a force to be reckoned with for many years to come.

Novak Djokovic has certainly proved that he is at least the fourth best player in the world, if not the third. We still have Nikolay Davydenko who does well on every surface, in every tournament week-in, week-out.

But Djokovic showed that he is only 20 years old but he has really matured in the last year. He is physically a little stronger and mentally he was up against Igor Andreev who is a very good clay court player - he has a basic game in some ways but has a heavy forehand and is a good mover. But he made Andreev look like a junior player.

Djokovic against Nadal is going to be a great semi-final. I can't wait.