Roger Federer produced the performance to end the conversation for good.
The greatest of all-time delivered as only he does, be it in Melbourne, Paris, London or New York.
It happened to be at the Australian Open on Sunday, as the Swiss maestro sealed grand slam number 18 with an enthralling win over Rafael Nadal in a final for the ages. In danger of being caught for the most majors won by a man, Federer came from a break down in the fifth set to win 6-4 3-6 6-1 3-6 6-3.
This was the dream final that was never meant to be between two of the greats, returning from injury and seeded ninth (Nadal) and 17th (Federer). Federer claimed his first grand slam since Wimbledon in 2012 after three hours and 37 minutes, and at the age of 35. That title at the All England Club appeared almost certain to be his last, particularly after a knee injury ruined his 2016.
Winning a couple of matches was meant to be enough for Federer at Melbourne Park this year. Instead, he was vintage, albeit at times inconsistent, highlighted by the final.
Federer delivered a stunning performance to crush Czech 10th seed Tomas Berdych in straight sets in the third round. That brought belief, enhanced with a five-set win over Kei Nishikori in the last 16.
Again in the final, he swung from brilliant to inconsistent, allowing momentum to go with - or against - him.
In 2009, Federer lost the final to Nadal at Melbourne Park as his level dropped late in the match. This time, they both produced in the fifth set. Incredibly, Federer reeled off five straight games, hitting 23 winners to go with just nine unforced errors.
The fast courts in Melbourne provided him with his chance, suited to his shot-making against opponents who have mostly made their livings being defensive. Not only did it help Federer, but the grand slam as a whole, as aggressive players were rewarded, highlighted by the early exits of Djokovic and Murray.
It led to him securing a grand slam title that had seemed so unlikely - and seal his spot as the greatest ever.