Verstappen, who controlled the early stages of the race on Montreal's Circuit Gilles Villeneuve, made his second and final pitstop with 27 laps to go, handing the lead to Sainz.
Six laps later, by which time the Dutchman had narrowed the gap to Sainz down to just under eight seconds, AlphaTauri's Yuki Tsunoda went off coming out of the pits.
