If Rafa Nadal wins the Australian Open title next Sunday, he could claim to be the greatest male tennis player of the modern era.
There are substantial factors to overcome, including the Melbourne heat, fierce rivals such as Roger Federer, Andy Murray and (especially) Novak Djokovic, as well as the Spaniard's relatively poor recent record in Australia, where he has made the final just once in his last four attempts.
But if Nadal lifts the Norman Brookes Challenge Cup in seven days, he will become the first man in the Open era (since 1969) to win all four Grand Slam tournaments at least twice. The others who achieved the feat - Rod Laver (1960-69) and Roy Emerson (1961-67) - did so outside what is known as the open era.
It's the ultimate measure of consistency and durability, across four surfaces.
Federer has won several titles in Melbourne, London and New York but only one at Roland Garros. Pete Sampras, Stefan Edberg and Jimmy Connors also never won in Paris, while Bjorn Borg was unable to win the Australian or US Opens. Ivan Lendl was consistent (two Australian Opens, three French Opens and a hat-trick at Flushing Meadows) but was continually frustrated on the Wimbledon grass. Djokovic is a Melbourne legend already (four titles in six years) but has yet to win the French Open and has won only once at SW19 and in New York.
Beyond that unique feat, if Nadal wins his 14th Grand Slam title next week, he will equal Sampras and be in prime position to overhaul Federer (17) for all-time career titles and become El mas grande.
There are always factors beyond statistics in sport but in tennis, they tend to be the best measure of quality and success.
It seems increasingly unlikely 32-year-old Federer will add to his haul, as his legendary powers are waning. He has reached just three of the last 17 Grand Slam finals, after making 15 of the 16 staged before that. The Swiss will still be a danger on grass but is unlikely to reach the pinnacle again on the slower surfaces.
Across his career, Nadal has averaged one final every two attempts and has won 35.1 per cent of those tournaments.
Since 2010, despite ongoing injury problems, his success rate has rocketed up, as he has taken almost half (46.7 per cent) of the major events he has entered.
Barring more serious knee issues, it seems likely the Mallorcan, still only 28, has at least two, possibly three, more Roland Garros truimphs left in him and would only need to win once more in Melbourne or New York to equal or surpass the Swiss.