Lewis Hamilton has sympathised with rival Sebastian Vettel after the Ferrari driver's title challenge was handed a major blow when he was forced to retire from the Japanese Grand Prix after just four laps.

Since losing his championship lead at the Italian Grand Prix in Monza, Vettel has taken just 12 points from a possible 75 after crashing out of the Singapore GP, starting last in Malaysia and most recently retiring early in the race at Suzuka.

Ferrari confirmed later that it was a spark plug problem that ended the German's race and most likely his title challenge as he is now 59 points behind the Briton, who won the race in Japan on Sunday (8 October).

The four-time Formula 1 world champion was only once at fault for his misfortunes in the last three races and Hamilton sympathised with him suggesting that he has been "incredibly unfortunate". The Mercedes driver is no stranger to such misfortune as he suffered a spate of engine issues during his failed title battle with Nico Rosberg last season.

"He's been very unfortunate through no fault of his own," Hamilton said, as quoted by Sky Sports. "I was excited to have a good race with Sebastian here but he's been incredibly unfortunate."

However, the three-time world champion is not taking his fourth title for granted despite his massive lead. Vettel only has a chance if Mercedes has a spectacular meltdown, which is highly unlikely.

There are four races left until the end of the campaign with 100 points for the taking. Hamilton will have to fail to finish at least two of them for the Ferrari driver to have any chance of winning his fifth title.

"I wouldn't say I have one hand on it," the Briton added. "There are still 100 points available. I'm still going to keep the pedal to the metal."

lewis hamilton
Lewis Hamilton has a 59-point advantage over Vettel in the F1 drivers' title race Getty