Mercedes' motorsport boss Toto Wolff has apologised on behalf of the entire team to Lewis Hamilton after he suffered a second retirement of the season.

Hamilton again finds himself playing catch up in the race for this year's Formula One world championship after failing to score in the Canadian Grand Prix on Sunday, with team-mate Nico Rosberg finishing second.

Although both cars suffered a loss of one of the energy recovery systems – the MGU-K – Hamilton was forced to retire after 47 laps as a consequence of the failure of his rear brakes.

Gallingly for Hamilton, title rival Robserg managed to work through the difficulties posed by the loss of power and brakes.

Although at one stage with a train of three cars behind him as they had closed down the gap to the leader, only Daniel Ricciardo in his Red Bull found a way past to claim his maiden victory.

With a 22-point cushion now to Rosberg, Hamilton is adamant he can again claw back the deficit, as he did when he trailed the German by 25 points following the season-opening race in Australia.

For his part, Wolff felt particularly bad for Hamilton post-race as he said: “First of all, we have talked and we are just sorry to have let Lewis down.

“It is a shame, particularly with the championship as close as it is, but he is in good spirits and he is a fighter and I have no doubt he will come back.

“As for Nico, he deserved to take those points because he had a car that was heavily handicapped against all the others.”

Rosberg’s stunning reliability record of two wins and five seconds from the seven grands prix to date naturally makes it very tough for Hamilton to continue to play the hunter.

It could yet be the much-maligned double-points system for the final race will be crucial for the 29-year-old Briton.

Attempting to find the positives for Hamilton from a bad situation, Wolff said: “How many races are we into the season? Seven. So we have another 13 to go effectively as we have double points last race.”

Suggested to Wolff that scenario could save Hamilton’s campaign, he replied: “It could, but we have to be careful about talking of an easy home run now.”

Wary of the threat slowly coming from Red Bull following Ricciardo's win, with reigning four-times champion Sebastian Vettel third, Wolff reined in thoughts of a walk in the park to claim both titles.

Although still 119 points ahead of the Red Bull in the constructors’ championship, and with Ricciardo 61 adrift of Rosberg, Wolff added: “Red Bull scored massive points and can close that gap pretty quickly.

“I guess it will come down to an end of season with double points.”

Initially, Wolff has to first investigate the cause of the failure of the MGU-K, with the anomaly being it occurred on both cars at almost exactly the same time in the race.

“They were racing at exactly the same pace and had exactly the same temperatures,” said Wolff.

“In that particular part of the MGU-K we saw temperatures which were higher than expected.

“We were unaware they could have such a detrimental effect. The MGU-K just shut down and we could not reset it.

“We told both drivers to manage the brakes, to be careful, because when you lose the electric motor and you lose the electric braking it leads to the brakes overheating massively.

“Both complied exactly to what they were told, although it was very marginal, so when Lewis entered in to the pits, and with his car stationary, the temperatures rose.

“When he went out again the pedal went soft. Nico was lucky not to have that.

“It is just another part which we have to analyse and understand as I guess this can happen. The consequence was obviously detrimental to the whole car, the brakes, and in particular to Lewis.”

Mexican Sergio Perez has hit back at Williams and Brazilian Felipe Massa after they accused him of dangerous driving in Sunday's Canadian Grand Prix.

Perez and Massa crashed on the last lap of the race in Montreal after the Brazilian, who was lapping faster on fresher tyres, smashed into the back of the Force India while trying to take fourth place.

Race stewards decided Perez had changed his line and handed him a five-place grid penalty for the next race in Austria, a punishment the Mexican was clearly reluctant to accept.

“It was very disappointing to lose such a strong result through no fault of our own,” he said in a statement issued through his team.

“I was following the same line and braking patterns as in the previous laps and I just got hit from behind by Massa. There was plenty of space on the left of my car to attempt a clean overtake and I cannot understand why he had to scrape by.

“I watched several replays of the incident and I can’t help but notice how Felipe turns right just before he hits me. I can only think he must have changed his mind and wanted to rejoin the racing line, his misjudgement cost us a big amount of points.”

Massa, who piled heavily into the barriers, said afterwards it was lucky he was not seriously hurt and the Mexican needed to learn how to behave.

“I talked to him at the medical centre. I was so disappointed with him,” the Brazilian said. “I said that he needs to learn. I wanted him to put himself in my place, because I had a huge crash and honestly I thought it was going to hurt.”

Rob Smedley, Williams's head of vehicle performance, also told reporters that Force India should have retired Perez after he reported brake problems.

“They told him to carry on if he could, and if you can’t then to pit, which seems to me to be a fairly terminal problem,” he said. “Why you leave a car out when you’ve got that sort of problem is beyond me.”

Perez, whose Mercedes-powered team are currently fourth overall and just 10 points behind third-placed Ferrari, rejected the suggestion that his car should have been retired.

“It was perfectly driveable with just some adjustments and we showed it up until the moment in which we were taken out,” said the Mexican, who held second place until the closing laps.

“Other cars out there had been in similar conditions for way longer than us and they finished the race without problems. If someone thinks you can keep two Red Bulls behind for as long as we did with so-called ‘terminal’ problems, they are clearly misguided.”