The US Open has always been a tournament where upsets happen almost every year. Even the biggest players have found themselves losing a match they were not expected to lose and sometimes against opponents ranked far below them. Some of the most memorable shocks have come in the opening rounds, while others have changed the entire tournament.

The 2026 edition already had an upset on the opening day of the tournament with 24 time grand slam champion Novak Djokovic losing his first round match to an unseeded player. From Novak Djokovic to Serena Williams, these are five US Open upsets that stand out and came at a time when not many expected it. 

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5 Biggest Upsets in US Open History

1. Mariano Navone def Novak Djokovic – 2026

Mariano Navone produced one of the biggest shocks in recent US Open history by defeating four-time champion Novak Djokovic in the first round. The unseeded Argentine won 7-6(5), 5-7, 4-6, 6-2, 6-1 in a match that lasted four hours and 36 minutes. Djokovic had never previously lost in the opening round at the US Open and the defeat also ended his search for a record 25th Grand Slam title. Djokovic struggled physically during the match while Navone managed to defeat him in five sets. 

2.Naomi Osaka def Coco Gauff – 2025

Naomi Osaka knocked out third seed Coco Gauff 6-3, 6-2 in the fourth round of the 2025 US Open. Gauff arrived as the defending champion while Osaka was still working her way back after returning to the tour following the birth of her daughter. Osaka played one of her best matches of the tournament, breaking Gauff repeatedly and finishing the match in straight sets to reach the quarterfinals. It was a completely one sided match which shocked the crowd.

3.Botic van de Zandschulp def Carlos Alcaraz – 2024

Botic van de Zandschulp stunned third seed Carlos Alcaraz 6-1, 7-5, 6-4 in the second round in 2024. Alcaraz had won the French Open and Wimbledon earlier that season and arrived in the US Open as one of the tournament favourites while Van de Zandschulp was ranked No. 74 in the world. The Dutchman beat him in straight sets and became the first player to beat Alcaraz at a Grand Slam since Novak Djokovic at the 2023 French Open.

4.Stan Wawrinka def Novak Djokovic – 2016

Stan Wawrinka saved one of the biggest performances for the final in 2016 beating defending champion Novak Djokovic 6-7(1), 6-4, 7-5, 6-3. Djokovic had won the US Open the previous year and was chasing another title but Wawrinka gradually took control after losing the opening set. The victory gave the Swiss his third Grand Slam title and his first US Open crown while Djokovic was left with an unexpected defeat in the Final match.

5.Roberta Vinci def Serena Williams – 2015

Roberta Vinci’s 2-6, 6-4, 6-4 semifinal victory over Serena Williams in 2015 was one of the biggest US Open upsets in the Women’s singles. Serena was the defending champion and was two wins away from completing the calendar-year Grand Slam after winning the Australian Open, French Open and Wimbledon. Vinci came back from losing the opening set and broke Williams late in the third, reaching her first Grand Slam final in the process. The result was one of the most unexpected ones in the tournament.