Novak Djokovic won his 19th Grand Slam title after fighting back from two sets down to beat Greece's Stefanos Tsitsipas in the French Open final.
Top seed Djokovic, 34, was in deep trouble before rediscovering his energy to win 6-7 (6-8) 2-6 6-3 6-2 6-4.
The Serb's greater experience shone through as fifth seed Tsitsipas wilted in his first Grand Slam final.
The victory moves Djokovic one major title behind the men's record jointly held by Rafael Nadal and Roger Federer.
Djokovic, who previously won at Roland Garros in 2016, has become the first man to win all four Grand Slams twice since the fully professional Open era began in 1968.
The world number one will have the opportunity to move level on 20 titles with his great rivals Nadal and Federer when he defends his Wimbledon crown later this month.
Follow all the reaction to Djokovic's stunning win at Roland Garros
After Tsitsipas saved one championship point with a nerveless forehand winner down the line, Djokovic remained calm to take his second attempt after four hours and 11 minutes with a clinical overhead.
His expression remained emotionless as he shook hands with Tsitsipas, before bursting into a manic roar in front of the area where his parents, wife Jelena and coach Marian Vajda were celebrating.
Tsitsipas was a picture of devastation as he slumped in his chair, draping his towel over his head to hide the full extent of his emotions.
Djokovic dishes out another lesson to younger generation
After Djokovic and third seed Nadal were drawn in the same half of the men's singles, it presented the strong likelihood of a new name in a Grand Slam final from the other side of the draw.
Tsitsipas was already being tipped to be that man after earning more match wins than anyone else on the ATP Tour in 2021 and enjoying clay-court success with titles in Monte Carlo and Lyon.
The question that has long been asked - and continues to be posed - is whether the younger generation could translate that into success over the old guard on the biggest stage of all.
The five-set format is long and arduous on body and mind over the fortnight. Time and time again, Djokovic has proved he has the physical and mental ability to outlast even the most talented opponents.
Initially, Djokovic appeared to be feeling the effects of Friday's intense semi-final win over 13-time champion Nadal.
Looking weary and bothered by the bright Paris sun, he struggled on serve and was uncertain with his shot-making as he trailed by two sets.
Yet, as history has showed, it would have been foolish to write him off.
In his last-16 match against Italian teenager Lorenzo Musetti last week, Djokovic fought back from two sets down for the fifth time in his career and showed signs he could do the same against Tsitsipas at the start of the third.
The pressure of a fifth break point told when Djokovic took Tsitsipas' serve for a 3-1 lead. Suddenly, momentum had completely shifted.
Djokovic remained largely calm as his precise hitting and rhythm returned, helping him ease through the fourth set and put him in control of the decider.
The extraordinary effort he put in to beat Nadal would likely have been rendered pointless by Djokovic had he lost to Tsitsipas in the one that mattered even more.
Another break early in the decider gave him the opportunity to serve out the championship and, with more than four hours on the clock, survived a slight wobble to crush Tsitsipas' dreams.