As unlikely as it seems, the upcoming Wimbledon tournament represents Roger Federer's last chance for true tennis immortality.
If, like last year, the Swiss can come up with a fairytale victory, his status as the greatest tennis player of all time will probably be cemented. He would then have 18 Grand Slams - and neither Rafa Nadal (12), Novak Djokovic (6) nor Andy Murray (1) seem likely to overtake him.
But if he doesn't grab an eighth title at the All England Club, he could leave the door open for others, particularly Nadal.
It is unlikely that Federer will add to his collection beyond this year's Wimbledon. The 31-year-old has reached three finals from the last 14 majors; still respectable but not in any way comparable to his previous 14 attempts, when he made the final day on all but one occasion.
Federer is not exactly waning; he's still a phenomenon and handling his twilight years much better than former greats such as John McEnroe, Ivan Lendl, Stefan Edberg and Boris Becker. But it's hard to see him winning slam events on the other surfaces and, by next year's Wimbledon, he will be just weeks away from his 33rd birthday. Even with clever scheduling and the motivation of the Rio Olympics, you can't defy time forever.