Naomi Broady and Dan Evans made it four Britons through to the second round of the US Open - with Andy Murray and Aljaz Bedene still to play.
Broady beat compatriot Laura Robson 6-7 (4-7) 6-3 6-4 to claim only the second Grand Slam main-draw win of her career.
Evans earlier saw off American Rajeev Ram 6-2 4-6 7-5 6-1 to join Kyle Edmund and Johanna Konta in the last 64.
Compatriot Heather Watson struggled with illness as she lost 6-2 7-5 to Dutch qualifier Richel Hogenkamp.
World number 73 Watson has now failed to reach the second round at Flushing Meadows in six attempts.