I don't believe Roger Federer is the player that he was. He struggled early in the tournament against players he would normally have put in their place fairly emphatically.
Tomas Berdych beat him in Miami and I think that really gave the Czech player some confidence.
Having said that before the match I did expect Federer to win, I didn't think that Berdych wouldn't have the strength mentally.
Berdych has struggled in the head department in the past but what was interesting today is how, when it got tough, he just laughed it off and he really did produce some amazing tennis in the final two sets to wrap up the win.
For Federer the loss will be tough to bounce back from. He really thinks of Wimbledon as his domain and with good reason; and this just compounds his quarter-final loss at Roland Garros.
He was pretty tough in his press conference, saying how he wants to continue playing for some time yet etc. And I think he will be around for at least a couple more years.
But it is fair to say he is no longer the player he was.
For Berdych is was an impressive win. It will do him the power of good heading into his semi-final against Novak Djokovic.
I think he finally sees himself as a top five player, which of course a lot of other people did a couple of years ago. But he can finally fulfil his potential and his big game is helped by the fast courts at Wimbledon this year.
If he can hold his game together then I wouldn't write him off winning the title in this kind of form.
Djokovic's game is coming together at exactly the right time.
He is unrecognisable from the guy who even started the tournament, back then I didn't give him a hope in hell of winning the title. But now he has a very good chance.
The Berdych match will be a fascinating encounter and Djokovic will go in as a slight favourite to win the match. But I wouldn't like to have to pick a winner, it really could go either way.
Rafael Nadal made a very slow start and was strangely sluggish. But I was alarmed at the way Robin Soderling faded after Nadal took the third set.
He pulled a bit of a stunt with his blisters when Nadal was about to serve for that third set at 5-4. He just sat down and wanted the trainer. It was very unfair and I think it's a rule that they should change smartly. Unless it's an emergency you shouldn't be able to call for the trainer when your opponent is about to serve for a set.
But Nadal gathered himself and went on to cruise to the win in the next set.
Andy Murray's win all seemed to hinge on the second set tie-break. Tsonga had an absolute aberration when he left the volley that went on to land on the line and it really affected his concentration.
Murray is looking pretty useful though and he now has a great chance of going all the way. Nadal is playing well, not his best, but well and I don't think we should get too excited.
But Nadal and Murray always have exciting matches - the first two sets of their match in Melbourne earlier this year was some of the best tennis I think we've seen in the past year or so.
Looking ahead to the women's semi-finals I think Serena Williams needs to be a little bit careful of a big puncher like Petra Kvitova.
She had a massive quarter-final win and she'll fight like a lioness. I can see her going toe-to-toe with Serena for points and even games but I just can't see her managing it for a whole match.
Tsvetana Pironkova has been a real revelation this tournament. And if she comes to court in the right frame of mind then she could win her clash with Vera Zvonareva.
Zvonareva has a habit of being very emotional and letting that affect her matches. It would almost be better for her to be playing Venus Williams I think. Can she cope with being the favourite as she will be against Pironkova?
I think she probably can and I would predict a Serena-Zvonareva final.