The cause of Lewis Hamilton's third power unit failure of the 2016 season is still unknown according to Mercedes technical boss Paddy Lowe.
Hamilton's brand new power unit failed with just 15 laps remaining of the Malaysian Grand Prix, costing him a potential 25 points and the lead of the drivers' championship.
Whilst a frustrated Hamilton vented his frustrations after the race, Lowe admitted they had let him down with reliability this season and would continue to do everything they possibly can to avoid any future problems.
"Malaysia was a bitter pill to swallow," said Lowe. "We let Lewis down in a big way.
"We are continuing to investigate the issue with his engine and are doing everything we can to ensure that it is first understood and then contained for the remainder of the season.
"As it stands, despite the failure of this engine, Lewis now has the same stock of power units as Nico [Rosberg] for the remaining five races – including used power units which he can fit for free practice sessions. So, hopefully there will be no further impact to his programme."
Toto Wolff added that, despite Hamilton's frustrations, he admires the way the Briton has handled the situation, which included meeting with his engineering team and giving a rousing speech to keep spirits high.
"We’ve talked amongst ourselves and said “how is this possible?” But there is no rational explanation or pattern in these failures," he added. "If there were, we would resolve it.
"We’ve had that discussion with him and he understands that we are feeling his pain too. Despite his frustration, he has been trying to pick the team up and we admire him even more than ever for that.
"We will bounce back from this together. It’s tough when these things come at a crucial point in a Championship battle. It’s a massive blow to his campaign. But the Championship isn’t over yet."
