Marina Erakovic was forced to fight all the way before reaching the second round of the WTA Bell Challenge in Quebec City.
The sixth seed lost the opening set to Mallory Burdette but managed to edge a tiebreak before going on to claim a 5-7 7-6 (7-4) 6-3 victory.
"The match was very tight. It could have gone either way," Erakovic, who lost in the 2011 final to Barbora Zahlavova Strycova, told the WTA website.
"In the second set I started playing a little better and was very lucky to pull it out.
"In the third set, I think she was feeling a bit more pressure and I was able to serve it out. It was a good match."
Eighth seed Caroline Garcia is also through to the second round after she overcame Aleksandra Wozniak 6-3 6-4.
Former champion Tamira Paszek crashed out, though, after a 6-2 6-1 loss to Christina McHale.
Ajla Tomljanovic needed three sets to end the spirited challenge of Maria Sanchez, with the Croat winning 6-2 2-6 6-3.