Katie Boulter had to dig deep to beat Sonay Kartal in an all-British tie and keep her bid for a third straight Nottingham Open title on track.
Boulter trailed in the deciding set and almost went a double break down before regrouping to win 6-4 1-6 7-5 and reach the quarter-finals.
Eighth seed Boulter also called for the doctor during the match after struggling with the hot weather.
“I am definitely proper British because I can’t handle the heat at all,” the 28-year-old said.
“I’m just glad I got over the line.”
Boulter is on a 12-match winning streak in Nottingham, having won her first WTA Tour title in the city two years ago.
The Englishwoman will now face American McCartney Kessler for a place in the last four.
“I feel like I step into my house when I come on to this court. I have such great vibes here,” Boulter said.
Boulter is the last Briton in the women’s singles after Welsh teenager Mimi Xu was beaten by Poland’s Magda Linette earlier on Thursday
