Three biggest upsets on Day 3 of U.S. Open

Day 3 of the U.S. Open saw defending champions Novak Djokovic and Coco Gauff taking care of business to breeze into the third round. Other top-seeded stars such as Alexander Zverev, Casper Ruud, Aryna Sabalenka and Zheng Qinwen also advanced at Flushing Meadows while facing minimal resistance. 

However, a few of the top-ranked players suffered upset losses.

World No. 8 Barbora Krejcikova (Czechia)

Fresh off her Wimbledon win, Krejcikova suffered a shocking straight-sets loss (6-4, 7-5) to unseeded Romanian Elena-Gabriela Ruse. The latter, a doubles specialist, was ranked No. 122 in the world heading into Wednesday's match and had never advanced past the second round at any major in her eight-year career.

In fairness to Krejcikova, the U.S. Open marked her first taste of hard-court action since February. After the loss, she rued not entering the events in Cincinnati and Toronto in the lead-up to Flushing Meadows.  

The loss also meant the wait for a back-to-back champion at Wimbledon and the U.S. Open persists. The last woman to do it? The great Serena Williams in 2012. 

World No. 17 Ugo Humbert (France)

The 26-year-old Frenchman rolled into the U.S. Open with a 26-18 singles record in 2024, including two title wins at Dubai and Marseille. Humbert also had an impressive showing against Carlos Alcaraz at Wimbledon, pushing the eventual winner to a hard-fought contest in the Round of 16. 

It's why his 5-7, 6-4, 6-4, 6-4 loss to unseeded Argentinian Francisco Comesana on Wednesday was least expected. After winning the first set, Humbert had no answer for Comesana's strong service game — the Argentine won 77 percent of his points on his first serve. Furthermore, Humbert committed 11 double faults, which Comesana capitalized on by holding serve on the other end. Comesana also dominated Humert at the net, with a 73 percent success rate on net approaches, outperforming Humbert's 54 percent. The dominance at the net gave Comesana crucial points to seal the upset win. 

World No. 13 Daria Kasatkina (Russia)

On paper, the 12th-seeded Russian was the favorite against unseeded American Peyton Stearns. However, the two women were 1-1 in their two previous major matchups in 2024. At the Australian Open, Kasatkina put away Stearns in a hard-fought contest in the opening round. The American turned the tables at Roland Garros with a straight-sets victory in the second round.

Stearns clinched the trilogy with a convincing 6-1, 7-6 win on Wednesday, advancing to the third round for the second consecutive U.S. Open. The 23-year-old Ohio native fell in the fourth round to 2023 Wimbledon champion Marketa Vondrousova a year ago. She will now face Croatia's Donna Vekic in the third round on Friday. 

The 22-year-old Stearns now owns five wins over top-20 players in her career, with all those victories coming either at a major or a WTA 1000 event. She's clearly one to keep an eye on.