Murray vows to find winning formula

Andy Murray has vowed to find the right formula to help him cope with the physical demands required to win a first Grand Slam (Murray 5/1 Men's Australian Open 2011-Outright) after his US Open third-round exit to to Stanislas Wawrinka.

The 23-year-old British number one missed his final chance to break his career Grand Slam duck this year when he crashed to a 6-7 (3/7) 7-6 (7/4) 6-3 6-3 defeat against his Swiss opponent in three hours and 56 minutes on Sunday night.

The match featured 13 breaks of serve and numerous breaks as both players required medical treatmeant, but Wawrinka (40/1 Men's US Open Outright) had the edge to progress and will face American Sam Querrey in the fourth round.

Murray must now focus on seeing out the season and looking ahead to 2011 when he will start his Grand Slam bid in Australia in January, where he lost to Roger Federer in the final earlier this year.

On his defeat he said: "I haven't been really tired in any long matches for a long, long time. In the third and fourth sets I was struggling physically and I got frustrated with that. I haven't been in that position for a very long time.

"I felt like my chance of doing well here was slipping away. I've worked very hard to give myself a chance of winning tournaments. When I was struggling physically, I got disappointed."

He added: "I still feel like I'm super fit, I just didn't feel great (today). There were a lot of things that I was feeling on the court. But, yeah, I just haven't felt that way for a few years now.

"I'm going to have to go look at why that was the case and try and get better."