Britain's number two Johanna Konta beat Monica Puig 4-6 6-4 7-6 (7-5) in their delayed match to reach the Nottingham Open quarter-finals.
The world number 147 took the deciding tie-break agains the Puerto Rican - who is ranked 58 places above her - after two hours and 19 minutes of play.
Konta, 24, and Puig broke each other twice in the final set after play was halted in fading light on Wednesday.
The Briton faces Monica Niculescu, of Romania, in the last eight on Friday.
"It's always difficult not to finish a match on the same day. I'm happy to get through," said Konta.
Konta faces a stiff task, against world number 61 Niculescu, as she seeks a third successive Nottingham semi-final spot.
"Difficult. That's definitely a word to describe her. I've never played her before so I'm looking forward to the challenge. I'll just take it a point at a time and try my best," said Konta.