Emma Raducanu's encouraging Miami Open run came to an end in a narrow quarter-final defeat by fourth seed Jessica Pegula.
Despite needing medical treatment, the 22-year-old Briton levelled the match before American Pegula clinically regained control to win 6-4 6-7 (3-7) 6-2.
In the second set Raducanu played some of her best tennis since becoming a teenage Grand Slam champion at the 2021 US Open.
The world number 60 held a 5-2 lead and had four set points in the eighth game, before calling to see the doctor.
She had her blood pressure taken and was given ice towels to cool down before resuming.