Daniela Hantuchova apologised to her doubles partner after knocking her out of the women's singles.

Hantuchova, who is unseeded at Wimbledon for the first time since 2004, came from a break down in the first set to gain a 6-4 6-3 victory over Ai Sugiyama, of Japan.

"It's never a nice feeling having to play Sugi because she's one of my best friends," said Hantuchova. "We've got such a great history together.

Hantuchova added: "She's a great person so winning or losing I knew always it was going to be a strange feeling for me, so I just tried to take it as another tennis match and not to think that she was on the other side. I said sorry after the match."

Hantuchova, from Slovakia, has been struggling with 'flu this week but will have the weekend to fully recover for her fourth-round match against Serena Williams, against whom she has already lost twice at Wimbledon.

Williams beat Italy's Roberta Vinci 6-3 6-4, while fourth seed Elena Dementieva needed just 59 minutes to book her place in the last 16 by thrashing fellow Russian Regina Kulikova 6-1 6-2.

Dementieva's next opponent will be another Russian, Elena Vesnina, who gained a 7-5 4-6 6-4 win over 14th seed Dominika Cibulkova, of Slovakia.

Tenth seed Nadia Petrova came from a set and a break down to complete a third successive win over Argentina's Gisela Dulko, the second-round conqueror of Maria Sharapova.

France's Virginie Razzano was given a free passage through to the fourth round when seventh seed Vera Zvonareva pulled out with an ankle injury.

Coaching Report: Daniela Hantuchova vs Laura Robson

By Nick BollettieriTuesday, 23 June 2009

APDaniela Hantuchova begins to assert herself against Laura Robson

Shouldn't Daniela Hantuchova have beaten Laura Robson more easily, given their rankings?

No. I've known Daniela since she was a small kid, she's studied for years at my academy. I ran into her outside Court Two yesterday just before the match and said to her: "Hey kid, you've got a lot of shit on your shoulders today, playing the Brit girl on the new court." She replied: "I know Nick, but I'm going to try to win." I said: "Daniela, that's bullshit. You can't think you're going to try to win. You ARE going to win. You have to believe that."

For the best part of two sets it didn't look too much like she believed it (credit to Laura) and that second set so very nearly got away. But the bottom line? She won. Her greater experience allowed her to pull herself together emotionally, then technically.

Has Laura Robson got the X-factor?

That would be a YES. Watching her match against Daniela, I was hugely impressed at how Laura, still only 15, controlled herself in that high-pressure environment of a first senior Slam, with added home pressure. She has a good serve that will become magnificent. (Ignore those double faults. They mean jack at this stage. She was just going for it).

Being a leftie gives her added dynamism, and when she learns to move that serve placement around a bit more and use the wide slice to the ad court, it will be an even more dangerous weapon. Her forehand is good, she drives the ball well and hits from the shoulder. If there was one area where I would look for improvement it is in Laura's movement. She's a big, strong girl for 15 and as she will need good conditioning.

In what areas can she improve her technique?

One thing that struck me was Laura's huge, circular backswing that is, frankly, just too big. If you didn't see it, visualise her two-handed drawing the racket back so her hands are someplace between her shoulders and head, which I think is too high and too complicated. When you're not hitting from a solid base – and any flaw in movement will lead to you being less steady – you will tend to make late contact and find it especially hard to hit the ball down the lines.

I would adjust the swing pattern to make it shorter and straighter. She already has a good touch on the ball. Now she needs to adding to her game by taking more balls in the air, and by volleying more. Working on lower body strength will also help to improve stability and movement.