Isner, the 10th seed at the Rogers Cup, lost to Croatian Ivan Dodig, 6-4, 6-7(4), 6-3 on the grandstand court Monday night at Rexall Centre. The match was originally scheduled for the afternoon in the stadium, but a lengthy rain delay wreaked havoc on the day's schedule.
"Obviously it was not easy," said Dodig, who was playing his first singles match in 10 weeks because of a broken rib. "It was long day for us, and of course changing the court it's also a little bit like making you to think about it."
Isner, who was not made available to speak to reporters, lost his opening match at last week's Citi Open to Steve Johnson and told reporters in Washington that he didn't think he "deserved" to play on a secondary court. Storms in the Toronto area caused play to be delayed two hours, and Isner and Dodig didn't get the centre-court spotlight.
That went to 13th-seeded Jo-Wilfried Tsonga, who beat fellow Frenchman Edouard Roger-Vasselin 7-6(3), 6-1. The nightcap on centre court featured Canadian wild card Peter Polansky beating 2013 Wimbledon semifinalist Jerzy Janowicz 7-6(5), 6-4.
Polansky, who grew up in nearby Thornhill, Ont., last won a match in Toronto in 2010 when he upset Austria's Jurgen Melzer. He said this felt like a bit of deja vu — notably because this was by the same score — but this time the 26-year-old had to bounce back from a challenge on what he thought was match point.
"There was a little bit of nerves trying to pull through and hold for the match," Polansky said. "When he hit that forehand wide, I was pretty excited."
Polansky will face second-seeded Roger Federer in the second round Tuesday night. He said facing the 17-time Grand Slam champion will probably be one of the highlights of his career.
Monday night represented another low light for Isner, who dominated with his big serve but couldn't handle Dodig's throughout the night. Dodig broke the six-foot-ten American in the third set and was able to finish things off from there.
"He's the guy who can beat everybody, and as well a great player for many years," Dodig said of Isner. "You could see that there was not so many breaks. It's tough for both of us, for me to return to him and for him as well. He's going aggressive and he wasn't missing a lot today."
In other night action, American qualifier Michael Russell beat France's Nicholas Mahut 6-3, 6-3 and Spain's Feliciano Lopez beat 14th-seeded Roberto Bautista Agut 7-6(7), 3-6.
Earlier in the day, France's Julien Benneteau had little trouble dusting off former world No. 1 Lleyton Hewitt, 6-1, 6-2. Benneteau and Hewitt endured two rain delays, the second of which lasted two hours.
"I tried to keep the same momentum and the same rhythm of the match," Benneteau said. "I just tried to stay focused to be able to play the same way."
Benneteau was leading 4-1 in the first set when the first brief rain delay occurred. He was up 4-2 in the second when storms moving through the Toronto area halted his and every other match taking place.
"The rain delay, it's never easy but it's for both players," he said. "I had two break points before, 15-40 and then a deuce. So it's never easy."
Benneteau also said it's never easy facing Hewitt, even though the Aussie is 42nd now and 11 years removed from being atop the world rankings.
"He's a great fighter and to beat him you have to play solid," Benneteau said. "You have to do a good match. It's the kind of player that if your level is not good enough, you don't win."
To open the tournament on centre court, 15th-seeded Marin Cilic got pushed to the limit before beating Denis Istomin, 6-2, 4-6, 7-5. The Croatian said Istomin was dealing with a shoulder injury that led to some unpredictability.
"He had some shots were coming off good, some not, and it was difficult to know what was going to come," Cilic said. "It got a bit complicated."
In other early action, France's Jeremy Chardy beat Argentina's Federico Delbonis, 6-3, 5-7, 6-4, French qualifier Benoit Paire defeated Colombian Alejandro Falla, 6-7, 6-4, 6-2, and American qualifier Tim Smyczek downed German qualifier Tobias Kamke, 6-3, 6-2.
The Rogers Cup Hall of Fame induction ceremony was also postponed because of the weather. Stefan Edberg and former Rogers Cup Master of Ceremonies Don Goodwin will now be inducted Tuesday night.
Follow @SWhyno on Twitter