The U.S. Open promised a star-studded mixed doubles competition. It doesn’t get much bigger than this: a GOAT and the best player of the last three years pairing up.Carlos Alcaraz and Serena Williams, still arguably the sport’s biggest female star, will team up next week in the U.S. Open mixed doubles tournament, giving the tournament its second duo of megastars for an event that was an afterthought played before mostly empty stadiums just two years ago.The announcement came two days after Alcaraz said he was ready to return from his wrist injury after four months on the sidelines, and less than 24 hours after Jannik Sinner announced that a knee injury would prevent him from competing in the year’s final Grand Slam.Jannik Sinner withdraws from U.S. Open with right knee injuryAva WallaceTalk about shifting the conversation.Alcaraz and Williams will take the court with a combined 46 Grand Slam titles in singles and doubles. Williams, the greatest female player of the modern era, won 23 Grand Slam singles titles and teamed up with her sister, Venus, to win 14 Grand Slam doubles titles.She also won two more in mixed doubles, teaming up with Max Mirnyi of Belarus to win Wimbledon and the U.S. Open mixed competition in 1998, when she was just 16. Those were the first Grand Slam titles of her career.The only team that will come close to matching them in terms of star power and pedigree — at least in singles — will be Novak Djokovic and world No. 1 Aryna Sabalenka, who have a combined 31 Grand Slam titles in singles and doubles. Sabalenka teamed up with Elise Mertens to win her maiden Grand Slam titles in 2019 and 2021.Alcaraz may ask for some pointers. He has only won Grand Slam titles in singles and hasn’t had much success the few times he’s played doubles. He and Rafael Nadal won two matches at the Paris Olympics in 2024 but lost in the quarterfinals.During a practice set ahead of those Olympics, Nadal kept having to instruct Alcaraz on the subtleties of doubles, telling him where to stand and trying to get him to stop trying to use his power to hit through two people at the net.He and Emma Raducanu lost decisively in the opening round of the U.S. Open mixed doubles last year, as Jessica Pegula and Jack Draper beat them 4-2, 4-2.Regardless of their results this time around, Alcaraz bent the tennis universe back toward himself with six words on social media Thursday morning.“I’m coming back. Here we go,” the defending men’s singles champion wrote.Williams and Alcaraz simply walking onto the court together next Tuesday in Arthur Ashe Stadium will produce a seismic moment for the sport.Alcaraz has been managing tenosynovitis, an injury in which fluid accumulates in the sheath that protects a key tendon in the wrist. The condition kept him out of two Grand Slams this year, with the Spaniard and his team taking a cautious approach to managing an injury tennis players fear most. Alcaraz pulled out of the French Open a month before it started and withdrew from Wimbledon nearly six weeks out.He planned to play the Cincinnati Open earlier this month to test out his wrist but pulled out just days before. Many in the sport expected him to skip the U.S. Open, rather than begin his comeback in the crucible of best-of-five set tennis. The mixed doubles could serve as a test run to determine whether his wrist has healed.Williams reentered the sport’s anti-doping system last fall, quietly signaling she was contemplating a comeback four years after she decided to “evolve away” from the sport. She gave birth to her second child in 2023 and mainly pursued business ventures and investments since leaving the court.As this season progressed, Williams began showing videos of training sessions on the court and in the gym. She played doubles at two events on grass in Europe in June and lost a tight three-set singles match to Maya Joint in the opening round of Wimbledon, where she tweaked her knee and had to pull out of playing doubles with her sister.Williams did not play again until earlier this week in Cincinnati, where she and her sister lost a match-deciding tiebreak to Marta Kostyuk and Peyton Stearns.In the days since, USTA officials have been on edge waiting to hear whether Williams and Alcaraz felt fit enough to accept one of three remaining wild cards into the mixed doubles field. Williams is also considering whether to accept the final remaining wild card into the singles competition.Venus Williams accepted one of those spots earlier this week. The USTA has kept one available for Serena if she wants it. The sisters are also expected to play in the women’s doubles competition.The two remaining wild cards in mixed doubles went to Karolína Muchová and Jakub Menšík, and Emma Navarro and Tommy Paul. Jessica Pegula and Taylor Fritz also re-paired together, gaining main-draw direct entry, after Jack Draper and Elena Rybakina respectively withdrew and picked up an injury.As in 2025, the mixed doubles is the headline event for what the U.S. Open calls Fan Week, which takes up the seven days before the main-draw singles competition of the Grand Slam begins.The tournament was wildly successful last year, attracting some 78,000 spectators over two days of competition and packing Arthur Ashe Stadium for the semifinals and finals. Sara Errani and Andrea Vavassori picked up $1 million for their win, but the highest-profile pair of doubles specialists for this year sees joint men’s world No. 1 Henry Patten, who has been outspoken on ATP Tour plans to cut doubles draws from 2028, uniting with women’s No. 1 Kateřina Siniaková.Most of the doubles specialists will play in an eight-team qualifying tournament Monday that will produce two teams for the main draw. Errani and Vavassori received a wild card into the main draw, since direct entries were based on singles rankings.The format is “fast-fours”: best-of-three sets to four, with a match-deciding tiebreak instead of a full third set until the final, which will have regular sets and a match-deciding tiebreak.U.S. Open mixed doubles fieldDirect entriesAryna Sabalenka and Novak Djokovic