Polesitter Esteban Guerrieri led the Firestone Indy Lights Grand Prix of Trois-Rivieres flag to flag, in a race interrupted by pouring rain, clinching his third victory of the season after holding off a series of late challenges.
Guerrieri's win capped off an impressive weekend for the Sam Schmidt Motorsports driver in which his fastest race lap of 58.5076sec was an open-wheel track record.
Team Moore Racing's Gustavo Yacaman finished second, matching a career best, while Firestone Indy Lights championship points leader Josef Newgarden of Sam Schmidt Motorsports finished third.
The race was red-flagged on lap 44 because of a downpour. The drivers were allowed a six-minute pit to switch to rain tires.
"It was a very tough race," Guerrieri said. "When it started to rain, it got a bit crazy, then the red flag came out and it was a whole new race."
The green flag came back out after three laps under yellow with Guerrieri in the lead, followed by Conor Daly and Peter Dempsey. On the restart, Daly made a move to the inside to pass his Sam Schmidt Motorsports teammate but spun and backed into the retaining wall, ending his day.