Katie Boulter battled back from a set down to beat Jodie Burrage 3-6 7-6 (7-4) 6-2 and win the Progress Tour Women's Championships.
Burrage is ranked higher at 289th in the world, but Boulter - who is returning from a back injury - was favourite to win the domestic tournament at Roehampton.
The 23-year-old's career-high ranking is 82 but she has slipped to 374 after four months away from tennis.
"I'm happy to get the win," she said.
"Sometimes you've just got to find a way and I felt like I did that today. To get my body through five matches is a huge bonus for me - that was the aim I came into this week with.