Roger Federer's surprise second round exit at Wimbledon this year has already led some to question whether the Swiss star's time at the top is now over.
Widely regarded as the greatest tennis player of all-time, the 31-year-old crashed out in four sets against number 161 in the world Sergiy Stakhovsky, raising more doubts about his chances of claiming that elusive 18th major.
Federer has won seven All England Club titles, with his most recent grand slam victory coming in 2012, when he beat Andy Murray in last year's final at SW19. But, after a poor showing at Wimbledon this time out, his long-lasting dominance might be coming to an end.
Currently ranked at world number three, Federer hasn't fallen outside the ATP rankings top four for the past decade, holding the number one position for a total of 302 weeks - including a 237-consecutive-week stretch between 2004 and 2008.
He's appeared in 24 Grand Slam finals, reaching the final in each of the four majors - Wimbledon, the US Open, the French Open, and the Australian Open - at least five times.
Federer made it through to 18 out of 19 major finals between the 2005 Wimbledon Championships and the 2010 Australian Open and is the only man to reach at least the semi-finals of 23 consecutive Grand Slam tournaments.
In celebration of R-Fed's illustrious career, GiveMeSport invites you to take part in the Roger Federer Quiz (above) and test your knowledge to see how much you know about the greatest tennis player of all-time.