The dream team of Serena Williams and Carlos Alcaraz got off to a winning start, but could not progress to the final stages of the mixed doubles competition at the US Open in New York on Tuesday.

Williams, an American considered by many to be the best women's tennis player in history, and Spain's seven-time Grand Slam singles champion Alcaraz fell to Switzerland's Belinda Bencic and Italy's Flavio Cobolli 5-4, 4-1 in the quarterfinals.

That result means Bencic and Cobolli advanced to Wednesday's closing phase in the unorthodox draw, with the semifinals and finals slated to take place back-to-back.

"We felt their aura for sure," Bencic said afterward. "It was an honor to play."

"Playing Serena and Carlos on Arthur Ashe is not easy," Cobolli added. "So now, maybe we take a beer."

Williams and Alcaraz had shown strong form earlier in their debut as a duo, defeating the New Zealand/Great Britain pairing of Erin Routliffe and Lloyd Glasspool.

But Bencic, a former Olympic gold medalist who has beaten Williams in the past, and Cobolli, the French Open runner-up who is enjoying a breakout singles season, proved to be too much.

Williams, making her competitive return to Arthur Ashe Stadium after previously retiring in 2022, clearly delighted the crowd in Queens by joining forces with Spain's Alcaraz, who was coming back from a months-long injury layoff himself.

The two superstars, dressed in coordinated purple and black jersey-type outfits, smiled as they bantered and joked on changeovers. The fans, who loudly cheered their arrival in the first round, were a bit more subdued during the quarterfinal contest.

Earlier in the day, another high-wattage partnership, 24-time Grand Slam champion Novak Djokovic of Serbia and four-time major winner Aryna Sabalenka of Belarus, also bowed out, after losing to the Czech Republic's Katerina Siniakova and Great Britain's Henry Patten in three sets in the round of 16.