Max Verstappen described the final stages of the Canadian Grand Prix as the "hardest laps" of his life as he fended off Mercedes' Nico Rosberg to take fourth place.
Verstappen held third during the early stages at the Circuit Gilles Villeneuve but had to switch to a two-stop strategy, slipping behind the one-stopping Williams of Valtteri Bottas.
Verstappen emerged in fourth place but found himself under pressure from Nico Rosberg, who had also made a second stop, triggered by a slow puncture.
Rosberg attacked Verstappen but the Dutchman defended and when the Mercedes driver attempted a move on the penultimate lap, he spun and dropped back from the Red Bull youngster.
"We did what we could today and that was a great job," he said.
"We wanted to finish on the podium in front of the Williams but soon realised we were suffering with a bit too much tyre degradation.
"I think a little bit of rain could have helped us today. At the beginning I saved my tyres and fuel as I knew I could not stay with the front two.
"When Daniel [Ricciardo] got close behind I then decided it was time to push.
"I am very satisfied with my performance but also with the new power unit, you could see it was hard for the Mercedes to try and pass on the long straight so we are making good progress.
"The last ten laps I really enjoyed, I would actually say they were the hardest ten laps of my life.
"I was in fourth for a very long time so didn’t want to give up that position. It was a very hard battle at the end of the race, his [Rosberg] pace was very strong but we managed to keep ahead and then the last lap was pretty spectacular."