MONTREAL -- It has been a difficult National Bank Open for Canadian men as both Felix Auger-Aliassime, Vasek Pospisil and Denis Shapovalov were eliminated from the men's singles tournament at IGA Stadium on Wednesday.

After placing fourth in the 2024 Paris Olympic Games, Auger-Aliassime was upset in the opening round of the Montreal NBO at the hands of world No. 33 Flavio Cobolli 6-3, 6-2.

"Obviously I knew it was going to be complicated, getting used to the conditions wasn't easy, but that's all in the past. Now I have to just focus on the future," said Auger-Aliassime.

"I definitely wasn't the freshest both physically or mentally, but that's no excuse. You always have to strike a compromise between rest and being fresh and playing matches in a tournament environment."

Neither player was able to find a break point in the opening phase of the match as the first set would have but a single break point opportunity.

Auger-Aliassime struggled with his serve all night, picking up five double faults and only making 46 per cent of his first serves in the match. Cobboli would eventually make him pay for that, breaking the world No. 19 en route to a first set win.

It would be more of the same during the second set, with neither player managing to mount much of a threat during their return games. Cobolli would again be the first to break after a series of impressive returns put him in an excellent spot to close out the match.

"He was serving quite well, even better than the last time we played. I have to give him some credit as well, there were some shots that were amazing from him and that were too good," said Auger-Aliassime. " (Cobolli) played a really good match, he's in good form and he's confident right now so bravo to him. I hope he has a good tournament."

The result would be sealed when Cobolli broke Auger-Aliassime for the third time, coming alive in the second set. The Montreal-born hard court specialist could not find a reply, capitulating after just over an hour of play.

It only got worse for Canadians that evening as Pospisil was forced to retire after less than 20 minutes of action against American Sebastian Korda.

Following an awkward landing from a serve, Posposil pulled up limping midway during the third game of the match and appeared to be favouring his left leg. Visibly emotional, the Canadian received treatment on the court and -- following a medical timeout -- tried to continue albeit with significantly restricted mobility, but ultimately could not go on.

"It's very disappointing, I was really excited for the tournament and I was playing well, but that's how it goes. That's life and that's sports," said Pospisil, who was also dealing with a sore back during his doubles match with Denis Shapovalov on Tuesday.

"The decision was easy because I couldn't put any weight on it. I felt great because I felt like I had no injury for the first time since last year."

Shapovalov was bounced earlier on Wednesday in a first-round loss to American qualifier Brandon Nakashima. The 23 year-old defeated Shapovalov of Richmond Hill, Ont., 6-4, 7-5 in a match that took one hour 38 minutes to complete.

Shapovalov looked poised to win the second set with him serving at 4-3, but Nakashima broke serve and then held on for the victory.

Shapovalov finished the match with five aces, five double faults, 15 unforced errors, and saving one of three break points. Nakashima had four aces, five double faults, 13 unforced errors, and saved four of four break points.

Seeded Americans got off to a good start at the men's singles tournament as Tommy Paul and Ben Shelton posted first-round wins Wednesday.

Paul, seeded 10th in Montreal, fired nine aces in a 6-4, 7-6 (2) win over Italy's Luciano Darderi. He is playing in his first tournament since teaming with Taylor Fritz to win men's doubles bronze at the Paris Olympics. World No. 13 Fritz was also in action as the American faced Mariano Navone, dispatching the Argentine 6-4, 6-1 in straight sets.

Paul's next match will be against Nakashima.

Shelton, seeded 11th, came back from a break down in the first set to defeat Kazakhstan's Alexander Bublik 7-6 (4), 6-2 on Centre Court. He will next face Alexei Popyrin of Australia.

Wild cards Liam Draxl of New Market, Ont., and Benjamin Sigouin of Vancouver were eliminated 6-4, 6-3 by German combo Kevin Krawietz and Tim Puetz in men's doubles to close out the evening.

This report by The Canadian Press was first published Aug. 7, 2024.