Cape Town - Roger Federer continues to defy the history books by competing at the highest level at the age of 37, but has revealed that he will quit if he stops winning big events.
There's no doubt the Swiss great still very much enjoys the game, and his desire to compete has not waned, but he would never want to be in a position where he's just making up the numbers.
"It’s something I actually still get excited to do," Federer said during an event for Roddick Foundation in Austin. "Like Andy, I also do feel I need to believe that I can beat the best so that I can win the biggest tournaments, because when you feel that that fades away, then it’s really also time to stop.
"You don’t want to hang around just to hang around. If you put everything in there, you actually enjoy what you’re doing - I enjoy the practices, I enjoy press conferences, I enjoy shining a light on Andy’s foundation or the charitable work that tennis players do - it’s a wonderful thing.
"So as long as my body holds up and all the other things are in place and my family is happy, I see no reason why to stop."
Roddick, who naturally also attended the event, said he knew the time was right to retire when he no longer believed he could compete with the best.
"Once I lost that belief, it started feeling like a job for the first time," he said.
"And I had just seen so many guys who had stayed out there two years, three years too long and ended up with kind of this animosity toward the game. We stand here now and I love the game. I watched everything at the US Open. But, no, I don’t really have regrets looking back.
"It has given me time to look at other things in the business world and with the foundation, to have it grow. So, yeah, I don’t have a lot of regrets. Maybe not beating him (Federer)."