The lefthanded Fernandez, who had not played since the French Open quarter-finals due to a foot injury, walked out to loud cheers from an adoring home crowd before beating Storm Sanders (27) 6-4 6-7(2) 6-3 for her first main draw win at the WTA 1000 tournament.

"After not playing for two months I had a lot of expectations for myself to play an amazing match," Fernandez, who lost to Emma Raducanu (19) in the Flushing Meadows final last year, told reporters.

"That everything's going to fall in and like my serve, my return, my forehand's going to work like I want it to.

"But it did not.

"I was just happy the way that I was stronger mentally to accept it in certain moments and then get back to work. So it's obviously not my best level but I was just happy that I was able to fight through all these emotions that I had for myself."

Fernandez, ranked a career-high 13th, had two match points at 5-4 in the second set but the Australian Sanders saved both before going on to win the tiebreaker and force a decider.

In the final set, Fernandez got the break to go up 3-2 and then had a gutsy hold of serve after a lengthy eighth game, which was punctuated by loud shrieks from the crowd when the court was invaded by a mouse.

Fernandez, who will also play doubles with her younger sister Bianca (18) to get more match practice, had a giggle but kept her focus and in the next game broke Sanders' delivery a second time to seal the win on her third match point.

"Of course it's going to be like extra hours on the legs, but that's what we want," she said about the doubles. "That's what we want to see if my body can take it."

Follow the results from the WTA Tour Open in Toronto on Flashscore.