Milos Raonic emerged as the only Canadian survivor from five starters on opening day at the U.S. Open Monday.
The fifth seed reached the second round over Japan's Taro Daniel with a 6-3, 6-2, 7-6 (1) victory.
Raonic had a smooth ride in the first two sets, but hit speed bumps as he tried to serve it out.
"Maybe just lacked a little bit of intensity," Raonic said after the match. "Where I needed to, I played well.
"It's really hard to gauge my level because of the way things went throughout the match. But I feel like just the way I've prepared for this event, I'm feeling more comfortable than any of the other ones, so that's a good thing."
The Thornhill, Ont., product saved two break points with aces in the 10th game leading 5-4 but hit the net with a backhand to make it 5-5 in the third set. The set went to a tiebreaker where Raonic finally got the job done.
Raonic took just over 90 minutes to earn victory with 20 aces and nearly 60 winners.
"I've been playing my best tennis this year," he said. "I put a lot of focus into this event. I'm glad to be here and start playing.
"I'm hoping to stay for as long as possible."
Vasek Pospisil fell victim to a shoulder injury sustained from practise last week.
The 46th-ranked Vancouver player who won the Wimbledon doubles title, lost to clay-courter Simone Bolelli 2-6, 6-4, 6-2, 3-6, 6-3.
Pospisil revealed that he hurt his shoulder on one serve last Tuesday but added that the problem is slowly healing.
Pospisil fired 13 aces but was weighed down by 51 unforced errors and managed only 21 winners. He won his only match in New York during his 2011 debut after also going out in the first round a year ago.
"I've not been serving much, I lost my rhythm," said the Canadian. "I still have pain in my shoulder and that's never a good thing.
"I couldn't serve like I usually do, that seemed like a big part of the match today. It's only my serve that's affected. But you're then not as confident on serve and not as loose on return games. It changed the whole outlook on the match.
"I'm not stressed about doubles, the shoulder is getting better. Four days ago I could barely serve."
Sharon Fichman of Toronto, Aleksandra Wozniak of Blainville, Que., and Montreal's Francoise Abanda were also eliminated in the women's draw.
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.