British number one Katie Boulter suffered a 6-1 6-0 defeat against Karolina Muchova in under an hour at the US Open. The match, moved under the roof of the Louis Armstrong Stadium due to heavy rain, marked the 30-year-old's worst grand slam loss of her career.
Boulter initially broke Muchova's serve in the first game, but the Czech player, a Wimbledon runner-up this year, subsequently took control. Boulter was unable to secure another game, losing all seven of her service games and committing 21 unforced errors compared to four winners.
In other British action, Jan Choinski, 30, was eliminated in the first round. His match against Dutchman Botic van de Zandschulp was delayed by rain, and he was ultimately beaten 6-3 6-1 7-6 (5) in just under two hours.