Lewis Hamilton thought that his Mercedes power unit was “going to fail” en route to a fifth-place finish at the Formula 1 Canadian Grand Prix.

Mercedes was already on the back foot heading into the weekend, delaying an engine upgrade after the team found that there could be reliability issues related to the performance enhancements.

The team, therefore, entered the weekend with the same engine which had been used during the six previous races in 2018. Ferrari instead used its new power unit and Red Bull benefitted from Renault engine upgrades.

Starting fourth, Hamilton was soon having problems; “From the start, I was down on power and my engine was saying it was over temperature and I couldn’t get the temperatures down.

“I just thought it was going to fail, and every single lap, I was kind of on the edge waiting for the power to drop away and disappear because it kept dropping and coming back and dropping.”

The team decided to pit Hamilton at the same time as the Red Bull drivers, who had both started on the hypersoft tyre.

During his stop the team removed some cooling panels, to help Hamilton take control of the overheating engine, although that compromised performance. In the process, Hamilton lost fourth to Daniel Ricciardo.

After Sebastian Vettel claimed his third victory of 2018 in Canada, Hamilton had slipped behind him in the championship. He now trails points leader Vettel by one point.