Sebastian Vettel retires from the Japanese GP after engine failure
A second engine fault in as many weeks for Vettel and Ferrari
Sebastian Vettel suffered a fresh and possibly decisive championship blow at the Japanese GP after losing engine power and retiring from the race.
Ferrari diagnosed the fault, their second engine failure in as many weeks, as a spark plug problem - and it hands Lewis Hamilton a huge title advantage with the Mercedes driver extending his lead to 59 points with just four rounds remaining after winning in Suzuka.
After a humbling at Ferrari's home race in Italy, Vettel has subsequently crashed out in Singapore before being forced to start the Malaysia GP from the back of the grid due to an engine failure in qualifying. His latest setback leaves his hopes of a fifth title hanging by a thread.
"It's normal to be critical, especially if things go wrong because it's part of our job," Vettel told Sky F1. "But I need to protect them [Ferrari] - they've done an incredible job so far.
"It's just a pity in the two races with the reliability issues. But it's like that sometimes and of course it hurts and I'm disappointed, but now it's important to get some rest and give my all for the last four races and see what happens."
Vettel's car was frantically worked on by Ferrari mechanics on the grid before the race as they took off the engine cover to try and fix the issue.
The German got off the line safely but quickly lost places and reported he was losing engine power on the straight. Both Red Bulls, Force Indias and a Williams had overtaken Vettel before Ferrari told the four-time world champion to retire the car after just four laps.
And it could be a huge moment in the title race after Hamilton held off Max Verstappen for the race win. He now has a 59-point gap to Vettel and could seal the 2017 Drivers' Championship at the next race, the United States GP.
"It's not quite as bad as Singapore for Ferrari but it's not far behind," said Sky F1's Martin Brundle - with Kimi Raikkonen finishing fifth after starting down in 10th thanks to a five-place grid penalty due to a gearbox change.
Ferrari and Vettel were under intense pressure even before the Japanese GP after back-to-back disappointments at the last two races.
Vettel crashed out in Singapore on the first lap, while an engine change in Malaysia meant he had to fight his way from the back of the grid to fourth. Hamilton only had a three-point championship advantage before those Grands Prix.
And his Suzuka nightmare also means Vettel has yet to claim a race win since the summer break - his last victory was at July's Hungarian GP.
"We still have a chance this year," insisted Vettel. "Obviously it's not as much in our control as we like but overall I think the team is in a good way.
"We are improving race by race and we got a lot further than people thought so for sure there are some positives, but today is not the day for that."