It was the opportunity Novak Djokovic had been waiting for. Jannik Sinner was on his way home before the third round. Carlos Alcaraz was absent, unable to defend his French Open title. At 39 and with his chances of winning a record 25th grand slam singles title running out, Djokovic’s two biggest rivals, who between them had won the last nine major titles and ended his quest at the last four attempts, had been cleared from his path. As the men’s draw in Paris was blown wide open, Djokovic was the only grand slam champion remaining in the tournament.

But then Djokovic’s dream of grand slam history was ripped up by the arrival of a new star. At 19, Joao Fonseca claimed the biggest victory of his career in a stunning upset of historic proportions. Across four hours and 53 minutes, the Brazilian became the first teenager to beat Djokovic at a grand slam. He did it with power, poise, and from two sets down, winning 4-6, 4-6, 6-3, 7-5, 7-5. Djokovic had only ever lost one match from two sets up in 279 previous attempts, to Jurgen Melzer in the 2010 French Open quarter-finals. Asked how he believed he could do it, a stunned Fonseca replied: “I actually didn’t.”

There will be a new men’s grand slam winner at Roland Garros this fortnight; for the first time ever in the Open era, the fourth round will begin without a former grand slam champion in the draw. If Sinner’s stunning defeat unlocked it – also from two sets up, while struggling with the heat, illness, and fatigue – Djokovic’s exit has reinforced it: an unbelievable, unthinkable tournament is now an unprecedented opportunity for someone. Perhaps it will be Alexander Zverev, the second seed. Or Casper Ruud, a former French Open runner-up. Perhaps it’s Fonseca, or fellow teenager Rafael Jodar. And that’s only one side of a wide-open bracket.

But it will not be Djokovic. “Incredible match to be part of,” he said. “Tough one for me to lose being two sets to love up. But huge credit for Joao for really deserving to win the match. He without a doubt was the better player in the important moments, in the crucial fourth and fifth… some amazing exchanges and points and he just found incredible shots, lines. It was just amazing from his side. Obviously not great for me to be facing a player playing at such a level. I don’t think I’ve done too much wrong with my game. He was just better.”

There was, though, a clear despondency in Djokovic’s tone. He refused to discuss the window of opportunity that has passed him by, shutting down the question while it was being asked. He bluntly said he does not know if he will be back at the French Open next year, when he will be 40 years old, although he said that last year, too. After reaching the Australian Open final at the start of the year, Djokovic had hardly played in the three months before the French. He was pushed to another long match, in the afternoon heat. “I ran out of gas,” he said. “I didn’t feel good at all on the court in the last couple sets.”

Fonseca’s first victory was dragging him there. The Brazilian, playing an idol he called the “GOAT” and taking to Court Philippe-Chatrier for the first time in his career, appeared overawed in the early exchanges. The 19-year-old has a rocket of a forehand, and a tendency to pull the trigger on sight. But with the sun beating down, the ball was flying out of the court. He found control in the early evening and as the conditions shifted. Suddenly, he was able to hang around with Djokovic in the rallies. Then, he found the bravery to execute. “He just played lights out tennis every time there was a decisive moment,” Djokovic said.

Fonseca’s big breakthrough came at last year’s Australian Open, when as an 18-year-old qualifier he knocked out ninth seed Andrey Rublev in the opening round. “Hype” has followed him ever since; patience not so much. This, though, was a major step in his young career, after reaching the fourth round of a major for the first time. He displayed his firepower, and his guts, winning a second match in a row from two sets down after his round-two victory over Dino Prizmic. “We all saw today why there’s hype around him,” Djokovic said. “The level was amazing.”

Down a break in the fifth set, Fonseca fought his way back and blasted his way through with effortless power. Serving for the match, Fonseca found himself break point down as Djokovic battled to stay alive. But Fonseca didn’t let his opponent touch another ball, firing three consecutive aces with his fastest serves of the match. “I felt like John Isner, but it was crazy,” he smiled.

“There’s a lot of excitement around him and rightfully so,” Djokovic acknowledged. “Hopefully he can be the next great thing and win slams.” If it could be the start of a new era, with a third obstacle in his path, it only increases the chance that Djokovic’s is already over.