Roger Federer has absolute belief in himself and it's pretty worrying for the other players.
He's starting to relax - I felt there were some nerves earlier in the tournament because he hadn't won the first two Grand Slams, but now he can smell the finishing line.
Roger can win in so many different ways and he's done it before. He's playing better and better and as a champion and favourite you want to save the best until last
He's going to be incredibly tough to beat.
The next man to get a shot is Lleyton Hewitt after he saw off Feliciano Lopez.
Feliciano struggled and that was because he had never been in that position before. It's not often as a youngster that you can go on to Centre Court and play your best.
Hewitt is just the sort of player you don't want to play in that situation because he plays every point so hard.
The way he contests every point is a real weapon - it's like having Sampras' serve.
A lot of times when you're losing you don't want to show you're giving 100% and still coming up short so you figure ways to talk yourself out of it. Lleyton never does that.
He's put on some muscle and that power has helped his serve so much. He's served 74 aces in the tournament, up among the leaders and that would have been unthinkable even last year.
Nevertheless, I'd like to hear what he thinks Federer's weakness are because I certainly haven't seen many.
Andy Roddick is still only 22, but there's a lot of pressure on him - both self-imposed and from the American public expecting him to follow up on his US Open win.
It's been difficult for him, but he's realising now that Wimbledon is tailor-made for him.
He wants to prove he can take it a step further. He knows it's difficult but then he also knows he's in with a great chance - the best is yet to come from Andy.
Looking ahead to the women's semi-finals, I've backed Maria Sharapova all the way through so I'll stick with her.
But of the two matches, I have to say that Venus has the better chance of an upset.
I fully expect Lindsay to get through. She's a great player with experience and one of the best strikers of a ball I've ever seen.
It's going to be difficult for Mauresmo to get over the obstacle of a Grand Slam semi-final against someone that good.
John McEnroe was talking to John Inverdale on BBC1.