US Open Senior Director of Player Relations Eric Butorac dropped a bombshell, revealing that Jannik Sinner inquired whether Serena Williams could be a potential mixed doubles partner.

Jannik Sinner has withdrawn from the U.S. Open mixed doubles event, where he was going to partner Katerina Siniakova, a day after illness forced the world number one to retire five games into his Cincinnati Open final.

Grand Slam singles champions such as Jannik Sinner, Carlos Alcaraz, Iga Swiatek and Madison Keys will be playing for a little extra money — OK, a lot of extra money, by any standard: $1 million to the winning duo — and trying to get their hands on a trophy in the U.S. Open’s overhauled mixed doubles tournament.

When it came to finding a partner for the newly formatted mixed doubles event at this year’s U.S. Open, it seemed like a no-brainer for Madison Keys.