Top seed Simona Halep grind out a 7-6(9) 4-6 7-5 win over Russian Anastasia Pavlyuchenkova at the Rogers Cup in Montreal.
She will now have little time to rest ahead of her third-round clash with Venus Williams.
Halep returned to close out a three-hour battle during which she required treatment for what appeared to be blisters on the bottom of her right foot.
Her match began on Wednesday but was halted because of rain with Pavlyuchenkova ahead 4-3.
The Romanian world number one will have a quick turnaround as she is set to cap the evening session with a battle against seven-time Grand Slam winner, Venus Williams.
Williams will also not be fully rested after beating Sorana Cirstea 7-6(4) 6-4 in a match that was postponed from Wednesday.
“I’m a little bit dead, to be honest. It’s a long time since I played my last match at Wimbledon.
“I will try to do my best to recover and fight next match,’’ Halep said in her on-court interview.
“She’s a champion and it’s always difficult to play against her.
“On hard courts, it’s more difficult. I will try to enjoy it and to have a nice atmosphere again.’’
Johanna Konta, who was leading former world number one Victoria Azarenka 6-3 3-0 on Wednesday before rain forced an overnight delay, returned to wrap up the match 6-3 6-1.
Up next for the British number one will be a clash with defending champion, Elina Svitolina.
U.S. Open champion, Sloane Stephens, the third seed, beat Spain’s Carla Suarez Navarro 6-2 7-5 to book her spot in the quarter-finals.
She will face Latvia’s Anastasija Sevastova, a 6-3 7-6(2) winner over German 10th seed, Julia Goerges.