Serena has that amazing will-power. I've witnessed many times her facing match point and fighting back to win
The intensity of the Serena-Elena Dementieva semi-final was incredible.
There was a lot of hope that Dementieva could see off Serena Williams in Thursday's first semi. I have seen the Russian many times in the last year when she has been the better player and ended up losing.
Before this match I thought she would play brilliantly and dominate and then go off the edge. And guess what? She played brilliantly for two-and-a-half hours and then she went over the edge.
Serena has that amazing will-power. I've witnessed many times her facing match point and fighting back to win. Once again she was at it against Dementieva and came through. (Serena won 6-7 (4-7) 7-5 8-6).
I've seen every match of hers at Wimbledon this year and been so impressed with her intensity and focus. Two years ago she was all over the place but this year is completely different - she looks very determined.
I felt awful about Dinara Safina's match with Venus Williams. (Venus won 6-1 6-0). I feel so sorry for Safina - I don't know where she goes from here. After the French Open final as well, she's had two devastatingly bad matches. (Svetlana Kuznetsova beat Safina in June).
We had one fantastic semi and one not so. Overall in the women's game, we have too many players who just belt the ball all the time - they don't have a defensive game.
We've seen how great Andy Murray is because he defends so well. The men's game has transitioned but some of the women still have to catch up.
Sabine Lisicki (who lost to Safina) has played with more intelligence but there can be some pretty mindless tennis sometimes with the women.
Ana Ivanovic and Safina have really let themselves down this year. All I see is them getting all pumped up. I'd like to see them more relaxed on the court so they can execute their shots.
I don't think I even gave Dementieva a chance against Serena, but what a match.
There wasn't a fraction in it in the first. Each set was so close and each set had its own drama. There were all the challenges, then the match point and the Russian has everything to be proud of.
Serena is such a warrior with the yelling and the screaming. Some say it's not very lady-like, but it doesn't matter. She has shown why she is one of the all-time greats.
It wasn't all good though. The Serena forehand showed signs of tension throughout and her sister must have enjoyed watching that weakness.
Highlights - Serena overcomes Dementieva
Serena served up some big aces - and at crucial times.
She also benefitted from the challenge rule more than in any match I've ever seen. It was brought in after a US Open quarter-final five years ago that involved Serena. And I think she may have lost this match without it.
It was a match we will all remember for a long time.
The Murray/Wawrinka five-setter was an incredible moment, plus Tommy Haas coming through over-night against Marin Cilic.
You need a Championships with many moments - otherwise it will just be all about Murray and the roof! Finally women's tennis will be getting the headlines.
I thought the second semi with Safina and Venus was going to be closer. Safina showed her frailties and I think she could use a break from the game.
She's done amazingly well to be number one. Everybody has criticised her because she hasn't won a Grand Slam but she's won all these Tour events and put herself on the line.
She deserves to be on top but it's time for a pause. She was still the youngest out of the four semi-finalists and she has a long way to go. Two years ago if you had said she'd have this run, I would have said you were crazy.
Highlights - Venus demolishes Safina
If she wants to be a force on grass her pull-back on the shots needs to be shorter. Looking at the two losers, Dementieva has everything to look forward to and Safina needs to re-group.
Venus never let Safina have one look at the match - that's the way she plays. I thought she would be a little stressed but you knew she'd be ready for it.
She had to watch her sister through all the three hours of drama and then had to come out and play.
But she's been through it all before. The story about these two African-American girls with their tough upbringing is one of the greatest in tennis.
Virginia Wade and Pam Shriver were talking on BBC Two's live Wimbledon coverage