Lewis Hamilton is braced for a painful week after he lost his championship lead to Sebastian Vettel in Canada on Sunday.
Hamilton now trails Vettel by one point after the dominant Ferrari driver marched to victory at the Circuit Gilles Villeneuve.
Hamilton could finish only fifth as he was left to rue Mercedes’ failure to bring a planned engine upgrade to Montreal.
The Briton reported he was down on power in the opening exchanges, and had to pit earlier than planned as his Mercedes team made changes to his overheating machinery.
Hamilton was overtaken by Daniel Ricciardo during the pit stops, and feared his seven-race-old engine would not make it the chequered flag.
“I thought it was going to blow,” Hamilton said.
“That’s why if I’m really honest, I’m sure the next couple of days it will get more painful.
“Every single lap I was waiting for the power to just drop away and disappear – but it kept going.
“It was ultimately a poor weekend for me, but it could have been a lot worse. I could have failed to finish and lose 25 points to Vettel.”
Mercedes have dominated the sport since 2014, but the fiercer competition provided by both Ferrari and Red Bull this year has led to a series of errors by the once-dominant team.
A timing glitch during a virtual safety car period cost Hamilton the win in Australia before a gearbox issue resulted in a grid drop for the Briton at the next round in Bahrain.
Mercedes can also be accused of playing it safe when they did not bring Hamilton in for new tyres following a late safety car in China.
And here, their failure to provide Hamilton with a fresh engine has contributed to him losing the championship lead.
“This is a major wake-up call for every single member of the team,” Mercedes boss Toto Wolff added on Sunday night.
“I’m the opposite of confident moving forward. Everybody needs to assess how to improve our performance.
“This year’s championship is going to be decided by the one who makes the least mistakes. This is the new reality.
“It is a three-way team fight and six cars can win races. We cannot take anything for granted and think it is going to be a walk in the park.”