McLaren's Formula 1 championship rivals Oscar Piastri and Lando Norris crashed into each other, as Mercedes driver George Russell triumphed at the Canadian Grand Prix.
Piastri was defending fourth place from Norris, who had been catching Australia's championship leader in the late stages of the race.
The teammates, separated by 10 points heading into Monday morning's race, were approaching the final chicane on lap 66 of 70 side-by-side.
Piastri stayed in front, but Norris then attempted to go up the inside of the Australian on the start-finish straight. Piastri defended, but Norris still attempted to go into a space that was not there, running into the rear of his teammate.
Norris's front wing fell off and he went into the barrier, while Piastri was able to survive the collision and maintain fourth place.
The British driver, who said leading into the weekend that a moment between the duo this season was "inevitable", took full responsibility for the collision.
"I'm sorry. It's all my bad," he said to his team.
"All my fault. Unlucky.
"Sorry. Stupid from me."
Norris would approach Piastri in the media area to apologise for the incident.
"No one to blame but myself, so I apologise to the whole team, and to Oscar as well for attempting something probably a bit too silly," he told UK broadcaster Sky Sports.
The result means Piastri now has a 22-point lead over Norris in the drivers' championship.
Piastri said the unfortunate moment should not change the way he or Norris continue to battle this year.
"We are both fighting for a world championship, and I am thankful to the team that they allow us to race and I don't expect anything to change on that," the Australian said.
Meanwhile, Russell drove a terrific race to secure his first win of the year.
Max Verstappen drove an equally sound race to claim second and launch himself back into the F1 championship picture.
Mercedes driver Kimi Antonelli, at just 18-years-old, showed maturity and skill beyond his years to claim third.
The Italian teenager overtook Piastri on the first lap and never relinquished it.
"I had a good launch, managed to get alongside [Piastri] and in the first corner tried to stay alongside as much as possible. I was really happy to stick that," Antonelli said.
Re-live all the action from the Formula 1 Canadian Grand Prix on the ABC Sport blog.
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