Serena Williams and Carlos Alcaraz US Open mixed doubles dreams ended in the quarterfinals, as Belinda Bencic and Flavio Cobolli produced a composed performance to defeat the star pairing 5-4(4), 4-1 on Tuesday.

The result brought a quick conclusion to one of the most anticipated stories of the 2026 US Open Fan Week. Williams was making her return to competitive action at the US Open after a four-year absence, while Alcaraz was playing his first competitive match in more than four months after recovering from a wrist injury.

The highly publicized partnership delivered plenty of excitement, but Bencic and Cobolli proved too consistent when the match reached its decisive moments. The Swiss-Italian combination advanced to the semifinals, while Williams and Alcaraz left the court after only two matches together.

Serena Williams Carlos Alcaraz US Open mixed doubles comeback

The pairing immediately captured attention because of the remarkable resumes of both players.

Williams, one of the most decorated players in tennis history, had not competed at the US Open since 2022. Her return to Arthur Ashe Stadium created a major moment before the main singles tournament had even begun.

Alcaraz, meanwhile, was using the mixed doubles event as a competitive return after missing several months because of a wrist problem. The Spaniard had been sidelined since April, making the tournament an important test before the singles draw.

Together, they represented two very different stages of a tennis career. Williams brought decades of experience and an enormous connection with the New York crowd. Alcaraz brought the energy of one of the sport’s leading young stars.

That combination made their first match one of the biggest attractions of Fan Week.

The pair defeated Erin Routliffe and Lloyd Glasspool in their opening match, winning 5-3, 4-1. The victory lasted less than an hour, but it gave fans an opportunity to see Williams competing on the Arthur Ashe Stadium court again.

Williams and Alcaraz make a fast start

The opening victory also showed why the unusual partnership could be dangerous in the short-format competition.

The revamped US Open mixed doubles format rewards quick starts. Sets are shorter, no-ad scoring creates additional pressure and matches can turn rapidly after only a few points.

Williams and Alcaraz appeared comfortable with that environment in their first outing.

Williams demonstrated that her timing and competitive instincts remained sharp despite her limited recent activity. Alcaraz provided athleticism and power from the other side of the court.

The crowd responded enthusiastically to their interaction. Their contrasting personalities also created a relaxed atmosphere, with the pair smiling and communicating throughout the match.

For Alcaraz, the victory was particularly valuable because it provided meaningful competitive court time before the singles competition.

For Williams, it was another reminder of the enormous interest surrounding her return.

Bencic and Cobolli spoil the star-studded occasion

The quarterfinal presented a much more difficult challenge.

Bencic and Cobolli entered the match without the same level of celebrity surrounding their opponents, but they had the tennis required to take advantage of the short format.

They eventually prevailed 5-4(4), 4-1.

The opening set was extremely tight. With the score level at four games apiece, the set went to a tiebreak. Bencic and Cobolli handled the crucial points better, winning the tiebreak 7-4.

That gave them momentum heading into the second set.

Williams and Alcaraz needed a strong response, but Bencic and Cobolli continued to play with discipline. They avoided allowing the atmosphere or the reputation of their opponents to dictate the match.

Bencic later acknowledged the unusual nature of facing two globally recognized stars. She said the pair could feel the aura surrounding Williams and Alcaraz, but they remained focused on the task.

Their reward was a place in the semifinals.

Serena Williams still provided flashes of brilliance

Although the result was disappointing for fans hoping to see more of the partnership, Williams still produced moments that showed why her return generated so much excitement.

The 44-year-old former world No. 1 displayed flashes of the power and accuracy that defined her career. She also embraced the occasion rather than treating the tournament simply as a competitive exercise.

According to reports from the match, Williams produced a 120 mph ace during the contest.

That moment was symbolic of the entire appearance. Even after years away from the US Open stage, Williams remained capable of producing elite-level shots in front of one of the biggest crowds in tennis.

Her participation also created speculation about what could come next.

Williams has already indicated interest in continuing to play doubles with her sister Venus. That possibility adds another intriguing storyline to her return to competition.

Alcaraz gets valuable preparation before the singles draw

For Alcaraz, the mixed doubles tournament served a different purpose.

The seven-time Grand Slam champion was primarily looking to regain competitive rhythm after his injury layoff. Rather than immediately entering a high-pressure singles match, he was able to compete in a shorter format alongside one of the most experienced players in tennis history.

That makes the two matches useful despite the early exit.

Alcaraz showed that he was able to move, serve and compete again at the US Open venue. The experience should give his team additional information about his physical condition before his singles campaign begins.

His return is one of the central storylines of the tournament because he enters the US Open as the defending men’s singles champion.

The mixed doubles defeat therefore should not be viewed simply as a failed title attempt. It was also part of Alcaraz’s broader preparation for the much longer singles competition.

The new US Open mixed doubles format creates instant drama

The Williams-Alcaraz partnership also highlighted why the US Open’s new approach to mixed doubles has attracted so much attention.

The tournament moved mixed doubles into Fan Week and placed greater emphasis on star singles players. The format uses shorter sets and no-ad scoring, with a match tiebreak used when necessary.

The goal is straightforward: make mixed doubles faster, more accessible and more attractive to mainstream tennis audiences.

The strategy has certainly created headlines.

In addition to Williams and Alcaraz, the 2026 field included other major names. Novak Djokovic and Aryna Sabalenka were among the headline pairings, but they were eliminated early.

That left the event with a mixture of established doubles expertise and singles stars competing in an unfamiliar environment.

The format also carries a $1 million top prize, increasing the stakes for players while giving fans another major attraction before the traditional US Open singles competition gets underway.

Bencic and Cobolli move into the semifinals

Bencic and Cobolli’s victory means the pair will continue their run against another high-profile combination.

They are scheduled to face Elina Svitolina and Gaël Monfils in the semifinals.

That matchup adds another compelling storyline because Svitolina and Monfils are married and have become one of tennis’s most recognizable couples.

The other semifinal features Karolina Muchova and Jakub Mensik against Mirra Andreeva and Andrey Rublev, according to tournament coverage.

The semifinal lineup demonstrates how dramatically the tournament has moved away from a conventional mixed doubles competition featuring only specialist doubles players.

Instead, the US Open has created a short, star-driven event designed to generate attention before the main tournament begins.

What the Williams-Alcaraz partnership leaves behind

The Serena Williams Carlos Alcaraz US Open mixed doubles partnership lasted only two matches, but its impact was considerably larger than the results suggest.

Williams’ return generated nostalgia and excitement among fans who had not seen her compete at the US Open for several years.

Alcaraz’s comeback provided an early indication of his condition ahead of his singles title defense.

Together, they also helped demonstrate the commercial and entertainment appeal of the US Open’s revamped mixed doubles format.

The defeat does not erase the significance of the appearance.

For Williams, simply walking back onto Arthur Ashe Stadium represented a major moment. For Alcaraz, the matches offered valuable competitive preparation. For the US Open, the partnership delivered exactly what the tournament’s new mixed doubles strategy was designed to create: attention, packed stands and conversations well before the singles championship begins.

Their run may have ended sooner than fans hoped, but the occasion was still memorable.

Bencic and Cobolli, meanwhile, now have the opportunity to turn their upset victory into something much bigger. Having eliminated one of the most celebrated partnerships in the draw, they enter the semifinals with growing confidence.

And for Williams and Alcaraz, the story may not be finished.

Williams has suggested that another doubles appearance with her sister Venus could be possible, while Alcaraz now turns his attention to the singles tournament and the challenge of competing after a lengthy injury absence.

Their mixed doubles partnership was brief. Its place in the opening story of the 2026 US Open, however, is likely to last much longer.