'I never expected this...": Serena Williams and Carlos Alcaraz stun US Open fans before quarter-final defeat as star pairing falls to Bencic and Cobolli

Serena Williams and Carlos Alcaraz’s much-anticipated mixed doubles partnership delivered one of the biggest moments of the US Open before their run came to an end in the quarter-finals.

The star pairing defeated Britain’s Lloyd Glasspool and Erin Routliffe in their opening match before fourth seeds Belinda Bencic and Flavio Cobolli ended their campaign.

For Williams, the appearance marked another remarkable return to competitive tennis at the age of 44.

Serena Williams makes winning US Open return

Williams, a 23-time Grand Slam singles champion, returned to tennis in June and secured her first professional victory since 2022 alongside Alcaraz. The pair overcame Glasspool and Routliffe 5-3, 4-1 in front of a packed crowd at Arthur Ashe Stadium.

They had a slow start but quickly found their rhythm, producing the kind of high-profile tennis that had fans inside the stadium on their feet.

"I never expected to be back on this court," Williams said. "I never thought this would happen."

The moment was particularly significant given Williams' history at Flushing Meadows. She won the mixed doubles title at the US Open in 1998, five years before Alcaraz was born.

Alcaraz returns after wrist injury

The match was also Alcaraz’s first appearance back on tour since April after a wrist injury kept the reigning men's singles champion sidelined.

The 22-year-old Spaniard is already a seven-time major winner and teamed up with Williams in a pairing that immediately became one of the biggest stories of the revamped US Open mixed doubles event. Before their quarter-final, Cobolli described Williams and Alcaraz as "the queen of tennis and the king of now." But the star duo could not maintain their momentum.

Bencic and Cobolli end star pairing's run

With their quarter-final scheduled immediately after their opening match, Williams and Alcaraz appeared to run out of energy. Bencic and Cobolli eventually prevailed 5-4, 4-1 to book their place in the semi-finals.

Their victory brought an end to a short but memorable partnership that had generated enormous attention before the tournament. The result also left fans wondering whether Williams could make another appearance in the women's doubles alongside her older sister Venus. Williams has already ruled out another singles comeback at Wimbledon.

Djokovic and Sabalenka suffer shock exit

Elsewhere, top seeds Novak Djokovic and Aryna Sabalenka suffered an early exit. The 24-time Grand Slam champion and four-time major winner Sabalenka won the opening set against Britain’s Henry Patten and Katerina Siniakova, but the doubles specialists fought back.

Patten and Siniakova won 1-4, 4-2, 10-2, with Siniakova sealing the upset with an ace on match point.

"It wasn't looking very good for a while, in this format we play one bad game and all of a sudden the first set's gone," Patten said. "We knew the same could happen in the second, and we played an amazing tiebreak. Kat acing Novak on match point was great."

US Open mixed doubles reaches semifinals

The revamped mixed doubles format is again being played before the singles main draw, following changes introduced last year.

Defending champions Sara Errani and Andrea Vavassori were eliminated in the first round by Mirra Andreeva and Andrey Rublev.

Andreeva and Rublev later defeated Diana Shnaider and Casper Ruud to reach the semi-finals.

They will face Karolína Muchova and Jakub Mensik, while Bencic and Cobolli take on husband-and-wife pairing Gael Monfils and Elina Svitolina.

The two semi-finals are scheduled for Wednesday, followed by a final that will use a more traditional match format with sets played to six games.