British number three Cameron Norrie retired from his Battle of the Brits match against Dan Evans through injury.
Norrie, 24, trailed 4-0 in the first set before retiring with a hip problem at the National Tennis Centre.
Norrie, ranked 77th, decided not to risk making it worse with the professional tour resuming this month.
Andy Murray continued his preparations with a win in the men's doubles which helped his Union Jacks team cut the deficit on the British Bulldogs.
Former world number one Murray, 33, won 4-6 6-3 10-4 alongside Lloyd Glasspool in their match against Kyle Edmund and Joe Salisbury.