World number one Andy Murray is confident he can stay at the top of the men's game and play on into his thirties -- as long as he can keep himself fit.
Murray, who turned 30 on Monday, has not won a title since the Dubai Open in February and was eliminated in the second round of the Madrid Open last week, but is preparing to defend his title at this week's Rome Masters.
"When I was starting out on the tour, that (30) is around the time when a lot of (players) would have stopped playing or started to struggle," Murray was quoted as saying by the Times.
"You never know how your body's going to be and your health. If that's fine, there is no reason why you can't compete at the top of the game into your early to mid-thirties.
"Not everyone is going to be able to do that, you don't know how good the generation coming up are going to be, if they're better than the current generation. If that's the case then I think it becomes more difficult, but I'm hoping it isn't."
Murray was out with an elbow injury earlier this year and is still playing his way back to full fitness ahead of next week's French Open.
The Scot, who faces Italian Fabio Fognini in the second round in Rome, acknowledged that he could take nothing for granted after beating Novak Djokovic to win the title last year.
"I think a lot can change in 12 months," Murray said.
"I mean, a lot can change in a week in tennis... So I don't think that just because you do well the previous year means that you're going to have a good event the next year."
"Fognini is one of the better clay-court players, for sure. He obviously will be highly motivated playing in Italy as well.
"I have had some tough matches with him in the past, so it won't be easy. I will definitely need to play well in that one to have a chance of winning."