Alcaraz showed his steely determination to win the epic in five hours and 29 minutes, the longest final at Roland Garros, soaking up the ovation from a thoroughly entertained Parisian crowd long used to Nadal’s reign during his run of 14 titles.
Sinner held serve in a tense five-deuce opening game lasting 12 minutes, but was broken when he fired a forehand wide, before hitting back from 2-3 and going on to snatch an intense first set following an unforced error by Alcaraz.
Relentless pressure from the baseline allowed Sinner to go a break up early in the second set and the top seed began to apply the squeeze on Alcaraz, who was on the ropes trailing 1-4 on a sunbathed Court Philippe Chatrier.
An aggressive Alcaraz came out fighting and drew loud cheers when he drew level after 10 games and then forced a tiebreak but Sinner edged ahead with a blistering forehand winner and doubled his lead after the clock ticked past two hours.
Alcaraz, who had never come back from two sets down, battled hard in the hope of avoiding his first loss in a major final and pulled a set back before saving three match points at 3-5 down in the fourth set, later restoring parity via the tiebreak.
He traded breaks in the decider but prevailed in the super tiebreak to win the longest Paris men’s final since tennis went professional in 1968 while Sinner had to digest a missed chance to add to his US and Australian Open wins after a doping case.