LONDON: Andy Murray has vowed to underline his credentials to become a grand slam champion by winning the ATP World Tour Finals in London.

Murray has lifted six ATP Tour titles this year but the British number one will end the year still waiting to win his first grand slam crown.

The 22-year-old's failure to translate his undoubted talent into victory at any of the four majors has led some to question whether he will ever be able make the breakthrough.

The closest he came this year was at Wimbledon where he reached the semi-finals before Andy Roddick ended his bid for the All-England Club title.

World number four Murray, beaten by Roger Federer in the 2008 US Open final, knows the pressure is on to end that run next year, so victory in the Tour Finals would send a significant message to his closest rivals.

The Scot, who faces US Open champions Juan Martin del Potro in Sunday's opener at the O2 Arena, said: "This tournament is just behind the grand slams, because you have to win five matches or four matches against the top players in the world.

"You might even have to beat the number one or number two in the world twice to win the event so it's not quite the same as a grand slam but it's a huge, huge tournament.

"Everyone views it a little bit differently but I still believe that I have a few chances, maybe one or two more chances, to win a grand slam.

"For me, the year's been a successful one. For some people grand slams are the be-all and end-all. I want to win one, I'm trying my best to win one and I'll work as hard as I can.

"I feel like I'm getting closer than I was a couple of years ago. I feel I'm a better player than last year. I had a few problems at the grand slams this year. The ones I didn't do so well in, hopefully next year I'll feel great going into all of them."

Murray's belief that he can use the London event as a boost for next year's grand slams will be tested to the full by a group that also contains world number one Roger Federer and Spain's Fernando Verdasco, with Rafael Nadal, defending champion Novak Djokovic, Nikolay Davydenko and Robin Soderling in Group B.

The strength of the eight-man tournament would be tough enough for a fully fit Murray, but after six weeks on the sidelines with a wrist injury, he is still easing himself back to his best.

"I've got a better record against all the top players this year so it's been my best year on tour without question and hopefully next year will be better," he said.

"My consistency this year has been superb. Physically I've felt like I've been a lot better this year.

"But I'm not putting too much pressure on myself this week. I might go out and do well because of that.

"Obviously, I haven't played too much in the last two or three months so I don't know exactly what to expect. Mentally I feel fresh and that's going to be important."