Lewis Hamilton vowed to "keep the pedal to the metal" and dismissed the notion that he has one hand on the Formula One world championship after increasing his lead over a luckless Sebastian Vettel at the Japanese Grand Prix.

Ferrari's reliability issues reared their ugly head again at Suzuka as an engine problem led to an early retirement for Vettel, leaving Hamilton to take full advantage for a crucial race victory that leaves him 59 points ahead of his rival.

Another Hamilton triumph at the United States Grand Prix would seal a fourth world title for the Briton if Vettel places lower than fifth.

But the Mercedes star is taking nothing for granted with four races still to go.

"I wouldn't say I have one hand on it. There are still 100 points available," he told Sky Sports.

"I'm still going to keep the pedal to the metal. 

"Of course, he's been very unfortunate through no fault of his own. These engines are so complex, but all I can really say is my guys do such a phenomenal job, they are just so meticulous, and so faultless with their procedures and procedures that go on back at the factory."

Mercedes boss Toto Wolff credited Hamilton for his performance and sympathised with Ferrari's woes.

"The misfortune of Ferrari is unbelievable, for the third race in a row," he said. "But Lewis drove a spectacular race.

"You have a DNF [did not finish] or two and suddenly the whole thing swings back around.

"We can relate to it. The Ferrari guys certainly feel awful at the moment.

"Maybe it's the development of the team. They made a huge step forward from 2016 to 2017, their car is super fast – it just lacks reliability and that is the next step."