Defending champion Novak Djokovic was just as surprised as Carlos Alcaraz at the US Open, losing 6-4, 6-4, 2-6, 6-4 to 28th-seeded Australian Alexei Popyrin in the third round on Friday night.

The second-seeded Djokovic was attempting to become the first player in tennis history to win 25 Grand Slam singles titles. Instead, he ended the year without claiming at least one major championship for the first time since 2017. That hadn’t happened since 2010.

Also of note: This is the first season since 2002 in which none of the three great men’s tennis players — Djokovic, Rafael Nadal and Roger Federer — have won a Grand Slam trophy.

The third-round exit is Djokovic’s worst performance at Flushing Meadows; the only other times he was defeated so early at the US Open were in 2005 and 2006. The man Djokovic defeated 18 years ago, International Tennis Hall of Fame member Lleyton Hewitt, now captains Australia in the Davis Cup and was sitting in Popyrin’s guest box at Arthur Ashe Stadium.

The 37-year-old Djokovic has reached the final in Ashe ten times, winning the title in 2011, 2015, 2018 and 2023.

On Friday, however, he made 14 double faults and looked physically slow and emotionally flat, perhaps still feeling tired after winning Serbia’s first Olympic gold medal earlier in August by beating Alcaraz in the final of the Paris Olympics.

The third-seeded Alcaraz entered the US Open as a tournament favorite, having won the French Open and Wimbledon. He admitted his energy was lower than he realized after being knocked out by 74th-seeded Botic van de Zandschulp 6-1, 7-5, 6-4 in New York on Thursday night.

Djokovic subsequently replaced Alcaraz as the leading contender to win the men’s title, according to BetMGM Sportsbook, but that status did not last long.