Wednesday 22 June 2016 18:53, UK
Novak Djokovic has won the Australian and French Opens already in 2016, but how hard is it to complete a calendar Grand Slam?
Only Don Budge and Rod Laver have won all four Grand Slams inside a calendar year meaning every great player since the late-70s has failed to replicate their feat.
As Djokovic gears up to challenge, we remember who fell before him…
The Swiss great has twice won a hat-trick of Grand Slams inside a calendar year, but on each occasion he failed to add the magical fourth. Unlike Djokovic this year, Federer never won the opening two Grand Slams to give himself a shot at a clean sweep.
In 2004, Federer failed at the French Open after being eliminated by three-time winner Gustavo Kuerten in the round-of-32. World No 1 and aged 22 at the time, Federer still won the other three Grand Slams of 2004. The same competition let him down two years later when, despite another three Grand Slams, he was beaten in the final by a peak Rafa Nadal.
In 2007, his familiar shortcomings in Paris reared their ugly head when Federer's calendar Grand Slam bid fell apart after another loss in the final to Nadal. In total, he has racked up 17 Grand Slams but never four in a year.
Like Federer, the Spaniard has never won the opening two Grand Slams of a year so has never been in a position to seriously challenge for all four. As Djokovic goes for No 3 of 2016 at Wimbledon, he will be reminded that nobody has won in Paris and London back-to-back since Nadal in 2008.
Nadal's best year was in 2010 when he won three of a possible four, but missed out on the first one. The Australian Open slipped through his grip in unfortunate circumstances - he withdrew injured in the quarter-final against Andy Murray when he was two sets behind.
That knee injury five years ago is still problematic and, having just withdrawn from this year's French Open, it seems like Nadal's chance at a calendar Grand Slam has long gone.
The legendary Australian completed a pair of calendar Grand Slams, dominating the circuit in 1962 and 1969. He reigned as the world No 1 from 1964 until 1970.
The '62 Australian Open was his third Slam in total, and springboarded him towards his first perfect year. He was an amateur in those days before going pro shortly after winning the 1963 Davis Cup with Australia.
And six years later, having already become Wimbledon's first Open era champion, Laver completed his second clean sweep including wins over the likes of Roy Emerson and Tony Roche.
The American won a remarkable six consecutive Grand Slams, including all four during 1938 to comprise his perfect 12 months.
Budge, among the world's top players in the late-1930s and early 40s, remains the youngest player to complete a career Grand Slam after completing the rout two days before his 23rd birthday.
In 1938 when Budge won all four Grand Slams, while the tennis scene was still entirely amateur, he became the first player to achieve the feat. He never lost a set throughout the whole of Wimbledon before beating Henry 'Bunny Austin' in the final.
Djokovic has claimed the first two Grand Slams of the year and back in 1988, Wilander did the same.
The world No 1 from Sweden never claimed a calendar Grand Slam because he fell short at the subsequent Wimbledon - a fate Djokovic is now looking to avoid. A quarter-final loss to Miloslav Mecir in London in 1988 did not stop Wilander jumping back on the horse to win the US Open, meaning he ended the year with three out of four Grand Slams.
