Roger Federer retirement question raised after Rafael Nadal sets new Grand Slam record

Greg Rusedski has asked whether Roger Federer would still be playing were it not for his great rival Rafael Nadal, who has pushed the Swiss on throughout his career - and vice versa. Nadal became the first male tennis player ever to win 21 Grand Slams by lifting the Australian Open title on Sunday, leaving Federer and Novak Djokovic behind on 20.

In an all-time-classic five-and-a-half-hour encounter in Melbourne, Russian Daniil Medvedev was two sets up and had three break points at 3-2 in the third set but Nadal rallied to win the last three sets and make history.

Nadal's second-ever Australian Open triumph makes him just the second man ever to win each Grand Slam twice in the Open Era after Djokovic.

Nadal, 35, has at least temporarily overtaken the Serbian, 34, in the battle to go down as the statistical 'Greatest [player] Of All Time'.

Federer meanwhile has been on 20 Slams since his glory Down Under in 2018 and despite turning 40 years old last August, will be back competing on the ATP Tour later this year.

He missed this year's Australian Open due to his ongoing recovery from knee surgery and it remains unclear whether he will be able to play his favourite major, Wimbledon, in June in what may be his final season on tour.

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And former British No 1 Rusedski has raised the question as to whether Federer would even still be playing if it were not for his long-running rivalries with Nadal and Djokovic, which have underpinned a glorious era of tennis for 15 years.

Writing in the Telegraph, Rusedski said: "As well as the stats, people also ask me who was the best when they were all at their absolute best? The answer is that it depends on the