Andy Murray's return to Grand Slam tennis ended in a four-set defeat by Spanish 31st seed Fernando Verdasco in the US Open second round.
The former British number one, playing his first Slam in 14 months, lost 7-5 2-6 6-4 6-4 in New York.
In sweltering conditions, Murray, 31, battled hard but did not have enough to overcome 34-year-old Verdasco.
It was only the Scot's fifth tournament back since having hip surgery in January.
Murray looked exhausted at times during a physical encounter on a humid Arthur Ashe Stadium - likely to be a combination of the conditions as temperatures rose close to 100F (38C) and his lack of five-set matches since being sidelined through injury.