Two Canadians have already exited the US Open.
Sharon Fichman of Toronto and Aleksandra Wozniak of Blainville, Que., were eliminated just an hour into Monday's first-round action at the last Grand Slam of the year.
Fichman returned from arthroscopic knee surgery to a crushing 6-1, 6-0 loss to fourth-seed Agnieszka Radwanska of Poland in a match that took 47 minutes. Wozniak lost to Japan's up-and-coming Kurumi Nara, 6-2, 6-1, in 59 minutes.
The No. 112-ranked Fichman was playing her first match since losing in the first round of Wimbledon on June 24. She had surgery to repair torn cartilage in her knee in late July, the result of injuries suffered in World Team Tennis.
"Only I know what I've been going through," she said. "Considering all that I have on my plate, I definitely did the best job that I could. I'm proud of my effort. I knew that even on the best of days, Radwanska would not be the easiest match."
Fichman is still searching for her first singles victory at a Grand Slam after first-round losses in New York last year and at Roland Garros and Wimbledon in 2014. She was rusty Monday, with 24 unforced errors and 23 winners from her Radwanska.
"I don't know how long it will take me to come back," said Fichman. "I'm doing the best that could be asked for after the surgery and the ankle and everything. I'll do all that I can, eventually I'll get there. All the struggles and hard work will make me better at the end."
The No. 97-ranked Wozniak suffered through 28 unforced errors as she ended her Grand Slam season without a victory at any of the three majors she played — Paris, London and New York.
The 26-year-old Canadian, who has struggled in her comeback from a shoulder injury several seasons ago, was playing her first elite-level match since losing in the first round of the Rogers Cup this month at home in Montreal.
"Obviously, I'm not happy with my game today," Wozniak said. "I didn't meet the expectations. She played well though, changing the speed and trajectory of the ball and I couldn't adjust.
"Nothing worked. It's been a pretty tough day at the office for me."
Wozniak said she has been struggling with a sore shoulder lately.
"We're almost at the end of the season and my shoulder seems fatigued," she said. "It's not in perfect shape at the moment. Bandages helped it. It's been bothering me for three weeks and it worries me a bit. But they tell me it's fatigue only. We'll see in the off-season what we'll do with that."
Woznaik said she is unsure if she will play in next month's WTA event in Quebec City.
Three other Canadians were in action Monday.
Fifth seed Milos Raonic of Thornhill, Ont., was set to open against Taro Daniel of Japan later Monday, while Wimbledon doubles champion Vasek Pospisil of Vancouver was scheduled to face Italian Stefano Bolelli.
Francoise Abanda was facing 2013 Wimbledon finalist Sabine Lisicki in the women's first round.