Djokovic and Sabalenka stunned in US Open mixed doubles opener as Serena Williams' comeback rolls on

The US Open's mixed doubles event delivered its share of upsets and storylines Tuesday, headlined by the shock first-round exit of top seeds Novak Djokovic and Aryna Sabalenka, and the continued comeback of Serena Williams, who reached the quarterfinals alongside defending men's champion Carlos Alcaraz.

Djokovic and Sabalenka, the No. 1 seeds in the revamped mixed doubles draw, fell to the world's top-ranked pairing, Katerina Siniakova and Henry Patten, by a score of 1-4, 4-2, 10-2 in the event's fast-paced, short-set format, according to an official recap published by the US Open. Djokovic and Sabalenka appeared in control after taking the first set, but Siniakova and Patten stormed back to force a match tiebreaker and closed it out with a dominant final-set performance.

Williams' return continues

A few courts away, the tournament's most closely watched storyline kept building. Williams, playing her first professional matches since 2022, teamed with Alcaraz to beat Britain's Lloyd Glasspool and New Zealand's Erin Routliffe in the opening round, giving the 23-time Grand Slam singles champion her first professional win in nearly four years. The pair followed that with a quarterfinal victory, extending Williams' comeback run and drawing large crowds to the mixed doubles courts, according to coverage from CBC Sports.

Alcaraz, who is also using the mixed doubles event as a competitive tune-up, is entering the tournament off a four-month layoff caused by a wrist injury and is looking to defend his men's singles title once the main draw begins this weekend. Organizers have credited the pairing of Williams and Alcaraz with generating some of the loudest atmospheres of the tournament's opening days, according to Sky Sports' tournament coverage.

For Djokovic, the early defeat is a minor setback as he turns his attention to the singles draw, where he is chasing a record 25th major title once first-round play begins this weekend. The 38-year-old had treated the mixed doubles event as both a warm-up and a showcase, but Tuesday's loss denies him an extended tune-up on Arthur Ashe Stadium's big stage ahead of singles competition. Sabalenka, the reigning world No. 1 in women's singles, will similarly shift full focus to defending her own singles crown.

Tournament organizers have leaned into the expanded, star-studded mixed doubles format in recent years specifically to draw top singles players into the event's opening week, and Tuesday's split results — a marquee upset alongside a sentimental deep run — delivered exactly the kind of headlines the format was designed to generate. The mixed doubles semifinals are scheduled for later this week, with Williams and Alcaraz among the remaining contenders as the tournament's singles draws prepare to take center stage.

Williams retired from professional tennis in 2022 after a farewell run at that year's US Open, closing out a career that included 23 Grand Slam singles titles, an Open-era record. Her return to competitive play this week, even in the doubles-only mixed event, marks her first official match action since that 2022 send-off. Alcaraz, for his part, is the reigning men's singles champion at Flushing Meadows and enters this week's mixed doubles run as a tune-up before he begins defense of that title in the main draw.