Sebastian Vettel's 2017 title bid in tatters after Suzuka DNF

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Sebastian Vettel's hopes of winning the 2017 world championship suffered another significant setback after an engine issue forced an early retirement at the Japanese Grand Prix.

The race in Suzuka looked set to be a fascinating duel between the two championship rivals, with Vettel starting second behind Lewis Hamilton. But it was apparent there were problems ahead of the race, with Vettel's car being frantically worked on before the start as Ferrari detected a spark plug issue.

The Ferrari driver started the race but it was immediately clear there was something still wrong with his car as he slipped back on the opening laps, losing places to Max Verstappen, Esteban Ocon, Daniel Ricciardo and Valtteri Bottas. Several laps later Ferrari called him into the pits to retire the car.

It leaves Vettel's title hopes in tatters and is another remarkable setback for a driver who was leading the championship just four races ago ahead of the Italian Grand Prix. It is the the third successive incident to hit the German -- he crashed out of the lead of the Singapore Grand Prix, allowing Hamilton to win and gain 25 points, before engine issues dogged his progress at the Malaysian Grand Prix.

Coming to Japan, Hamilton led by 34 points and, with 25 points on offer for a victory, he could wrap up the 2017 world championship at the U.S. Grand Prix at the Circuit of the Americas in two weeks' time.

Ahead of this week, Ferrari president Sergio Marchionne confirmed he will be making organisational changes to the team's "quality department" in a bid to ensure reliability issues did not continue after the events of Malaysia.