Novak Djokovic finally got his hands on an Olympic gold medal to complete the career Golden Slam in Paris but the Serb faces the prospect of being shut out of the Grand Slams for the first time since 2017 as he gears up for his US Open title defence.
Djokovic, who will once again bid for a record 25th Grand Slam title at Flushing Meadows, has been upstaged by younger rivals this season, losing to Jannik Sinner in the Australian Open semifinals and Carlos Alcaraz in the Wimbledon final.
The 37-year-old withdrew from his French Open quarterfinal due to a knee injury.
The last time Djokovic played all four majors in a season without winning one was 14 years ago but recent form suggests he is getting back to his best with the Serb beating French Open champion Alcaraz in the Paris Games final at Roland Garros.
Djokovic has since opted out of US Open tune-up tournaments in Montreal and Cincinnati to recharge his batteries before attempting to move past Margaret Court and take sole possession of the all-time Grand Slam record.
"I think he can find the motivation, the gold medal will lift him. If he plays like this, he's the man to beat at the US Open," Djokovic's former coach Goran Ivanisevic said.
"I'm so glad that he finally won the Olympic gold. I wish him a 25th Grand Slam, to break the absolute record, and then he can retire, although he'll never retire."
Alcaraz arrives in New York slightly undercooked on hardcourts and hoping to erase Friday's racket-smashing defeat by French veteran Gael Monfils in the Cincinnati second round.
"I felt it was the worst match I ever played in my career," Alcaraz said of the 4-6, 7-6(5), 6-4 loss.
"It's really difficult to find good stuff from this match. I want to forget it, and try to move on to New York."
Also standing in Djokovic's way could be 23-year-old world No. 1 Sinner, who won his first major title earlier this season after dethroning the Serb at the Australian Open.
The Italian missed the Olympics due to tonsillitis and has struggled with a lingering hip issue, but peaked in time for the August 26-September 8 US Open by winning the Cincinnati crown.
"I'm happy to be in the position I am, just trying to keep going mentally, having this hunger to keep playing and hopefully I can show some good tennis in New York," Sinner said.
"It's important to recover, to be ready for New York. This is our main goal for this US swing."
Sinner heads into the US Open amid controversy having failed two drug tests in March but was cleared of wrongdoing by an independent tribunal after it accepted his explanation that an anabolic agent entered his system from a member of his support team through massages and sports therapy.
World No. 4 Alexander Zverev will continue his quest to claim a maiden major, as will sixth-ranked Andrey Rublev and eighth-ranked Casper Ruud.
Daniil Medvedev, the 2021 champion, will need to shake off a run of poor form if he is to mount a challenge.
A group of American men including Taylor Fritz, Ben Shelton, Tommy Paul, Frances Tiafoe and Sebastian Korda will look to end the country's 21-year Grand Slam drought since Andy Roddick's triumph at his home major.
"All the Americans are playing really great tennis right now," said Korda, who won the Washington title. "Hopefully we can make a big push in the coming Grand Slam soon."