What happened: The pair received a wild card into the mixed-doubles field. They will face Erin Routliffe and Lloyd Glasspool in Tuesday's first round.
Why it matters: Williams is playing her first US Open match since 2022 and is not entered in singles. Alcaraz returns as the defending men's singles champion.
By the numbers: The first round and quarterfinals are Tuesday, followed by the semifinals and final Wednesday.
What to watch: Their opening result will determine whether they return for Tuesday's quarterfinals.