British number one Dan Evans retired from his men's doubles match a day before his third-round tie in the singles at the US Open.
Evans, alongside compatriot Lloyd Glasspool, were trailing 7-6 (7-4) 4-6 1-2 to Marcus Daniell of New Zealand and Brazil's Marcelo Demoliner.
Evans, who appeared to have discomfort in his inner thigh, faces Alexei Popyrin in the singles on Friday.
That match is second on court 17 so is expected to start at around 18:00 BST.
Earlier on Thursday, Britain's Jamie Murray and Brazilian partner Bruno Soares booked their place in the second round of the doubles.
They beat American Tommy Paul and Australian Popyrin 6-4 6-2 on court 14.
The seventh seeds fell to an early break but came back to win the first set before racing to a routine victory.
There was also victory for Britain's Dom Inglot and American partner Austin Krajicek, who beat Finnish pair Henri Kontinen and Harri Heliovaara 7-5 4-6 7-6 (12-10) in a gruelling encounter
However, British duo Ken Skupski and Luke Bambridge lost 6-3 6-3 to Slovakia's Filip Polasek and Australian John Peers, the eighth seeds.
Jonny O'Mara and Aisam-ul-Haq Qureshi of Pakistan play Uruguayan Ariel Behar and Ecuadorian Gonzalo Escobar later on Thursday.
Murray and Inglot join compatriot Joe Salisbury, who sealed his place along with American partner Rajeev Ram in the second round with victory on Wednesday.
In the women's doubles, Britain's Harriet Dart was knocked out alongside Taiwanese partner Chan Hao-ching after they lost 7-6 (7-5) 7-6 (7-5) to French duo Fiona Ferro and Alize Cornet.