The four Grand Slams - Australian Open, Roland Garros, Wimbledon and the US Open - are the blue riband events on the tour. These are the tournaments where the winners get the most 'value' for their wins, both in terms of ranking points and prize money.
These are the only tournaments where the male singles players slug it out over a 'best-of-five' set format, in an ultimate test of skill as well as endurance. The ethereal beauty of five-set matches lies in the fact that they take a lot of time and thus have the potential to acquire an epic status.
Many epic men's singles Grand Slam matches over the years have fallen short of true greatness only because they didn't go five sets.
Among active players, the trio of Roger Federer, Novak Djokovic and Marin Cilic has 30 five-set wins apiece. That win tally is matched or surpassed by only seven other players, led by Ilie Nastase (39) in the all-time list.
With the conclusion of the 2019 US Open, the Grand Slam season has drawn to a close. There were a total of 96 singles matches which went the distance. Wimbledon had 21 five-set matches, the Australian Open and Roland Garros registered 24 each, while the US Open witnessed 27 such matches.
Here is a pick of players who have won the most five-set Grand Slam matches this year.
Thomas Fabbiano - 3
The diminutive Italian followed up his first match win at the Australian Open with a five-set defeat of the 6'11" giant American Reilly Opelka 6-7 6-2 6-4 3-6 6-4 en route to the third round where his run was ended by Bulgaria's Grigor Dimitrov.
In his third appearance in the Wimbledon main draw, Fabbiano beat young Greek Stefanos Tsitsipas 6-4 3-6 6-4 6-7(8) 6-3 for the first top 10 win of his career. The Italian was then stretched the distance in the next round by Ivo Karlovic before emerging a 6-3 6-7(6) 6-3 6-7(4) 6-4 victor.
With the victory over Karlovic, Fabbiano improved his unbeaten five-set record to 5-0.
At the last Grand Slam of the year, Fabbiano registered the second top 10 win of his career by knocking out Dominic Thiem in the first round. The Italian looked on course for a sixth five-set win of his career when he led Alexander Bublik in the second round by two sets, only to lose the next three sets and see his perfect five-set record come to an end.