ANDY Murray admits that his ATP World Tour Finals record is a source of regret. The Scot's 7-6 (4), 6-4 defeat to Stan Wawrinka gives him an additional weekend to prepare for Britain's Davis Cup final tie against Belgium next weekend, but the 28-year-old from Dunblane cut a frustrated figure in the o2 arena last night, venturing back out on to court at around 11pm to take things out on a small yellow ball. Shortly beforehand, he had spoken of his disappointment at the costly errors which mean that only twice has he reached the semi-final in his six visits since this event moved to London. By contrast Wawrinka has reached the last four in all three of his , and it is he who faces his countryman Roger Federer on Saturday evening in the semi-finals. Should Federer win that match and go on to beat either Rafa Nadal or Novak Djokovic in Sunday's final, it may be the veteran Swiss, and not Murray, who will be World No 2 going into January and the Australian Open.

"When you're playing and competing against the best players, obviously it's very important," said Murray. "It doesn't matter whether it's in a smaller event or here. So that's why I'm disappointed with the losses the last two days. But this is obviously a big event, one I would have liked to have done better at over the years. It just hasn't quite happened for me and I'm disappointed about that. I do enjoy playing here. Great crowds, good atmosphere. It's a really nice venue to play in and I wish I could have done better."

While Murray's preparation for this tie was hardly ideal, spending chunks of time hitting on an indoor clay court, typically the Scot refused to make any excuses. Instead, he chided himself for making more errors as the week went on. Not that he felt such timing issues would hinder him unduly on his Davis Cup date with destiny next weekend.

"To be honest, it's not an excuse," said the World No 2. "I hit enough balls on hard courts the last five months. I said I felt like my timing would get better as the event went on, and it didn't actually, it got worse, which is strange. So that is nothing to do with not having enough time to prepare. I don't think that's a valid reason.

"Right now I'm not thinking about next week," he added. "But timing's never normally something that is an issue for me. I normally strike the ball fairly well. It is one of the stronger parts of my game. So that's something that I would imagine would come back fairly quickly."

No-one could point any fingers at Murray for lack of application here. He competed ferociously only to play an error-strewn tie-break in the first set, then almost battled back from a double break down in the second. The racket which he smashed on the court shortly after failing to capitalise on a break point as Wawrinka served for the match was testament to his desire to win.

"There was just way too many errors the last two matches," said Murray. "Everyone obviously can make mistakes. It's just more on easy shots, cheap errors. Just something really for the most part of this year I haven't been doing. But this week and actually a lot of the time when I've played here on this court, I've felt the same way. I made too many mistakes.

"I'm just trying to give reasons for why I lost the match," he added. "I'm not trying to take anything away from Stan. He serves big. At certain points in the match, he was hitting the ball very hard off both sides, playing sort of high-risk tennis, making a lot of winners.

"There was a period in the middle of the second set where he played extremely well, a lot of passing shots, hitting clean winners onto the line. There's not much I can do about that obviously. Sometimes when you're playing against the best players in the world, they can play great tennis.

"But just from my side, on the important moments I'm a bit disappointed with how I played them. If he had hit clean winners or played great points at 4-2 in the tie-break, you come in and you say he was too good at that moment. But in the tie- break, I made bad mistakes at the wrong time."