Jannik Sinner has withdrawn from the US Open mixed doubles event, where he was going to partner Katerina Siniakova, a day after illness forced the world number one to retire five games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.
The reimagined mixed doubles competition, a two-day event featuring 16 teams, began on Tuesday but the official draw and order of play no longer featured the Sinner-Siniakova entry.
Danielle Collins and Christian Harrison replaced the Sinner-Siniakova partnership in the draw and will play Belinda Bencic and Alexander Zverev in the first round.
Sinner, the reigning Australian Open, Wimbledon and US Open champion, looked uncomfortable in sweltering conditions on Monday at Cincinnati where he retired after falling behind 5-0 in the first set.
The main singles draw at the US Open is scheduled to begin on Sunday.

Daniil Medvedev handed Dubai title after Griekspoor withdrawal
England beat New Zealand to keep Pakistan's T20 World Cup hopes alive
Medvedev to face Griekspoor in bid for second Dubai title
Real Madrid face Man City again in Champions League knockouts
India defeat Zimbabwe to revive T20 World Cup hopes