5 reasons why Serena Williams is tennis' definitive GOAT

3. Unprecedented longevity in the sport

Williams went pro in 1995, winning her first major at the 1999 US Open – pictured

Serena Williams is succeeding at 35, yes, but she has enjoyed success for nearly two decades, since she first burst onto the scene. At only 18, the American won her first Grand Slam title – at the US Open, where she went on to win another five titles.

Williams has won a minimum of three titles on every surface she has played – a feat no player in the Open Era has achieved, barring German ace Steffi Graf, whose 22-Major record Serena beat this year with her win at the Australian Open – her 23^rd Grand Slam.

That in itself requires unprecedented consistency month on month, year on year, and Williams has done it all with aplomb!