Lewis Hamilton believes the challenge of leading Mercedes in a season-long battle against Sebastian Vettel and Ferrari has made this year the hardest of all the seasons in which he has competed for the title.

On Sunday, the 32-year-old became the most successful British driver ever after claiming his fourth Formula 1 championship and third since 2014 after finishing ninth in Mexico.

But while he might have had closer battles than this season against the likes of Nico Rosberg, Fernando Alonso, Kimi Raikkonen and Felipe Massa, winning the 2017 title with two races to go, the amount of effort that has gone in is what particularly stands out to Hamilton.

“I definitely think this has been [the hardest]," he explained. "2007 was difficult (when Hamilton missed out on the title by a single point), 2008 was very tough. The following years have just been different.

"This year, being in a position to really lead the team and help drive, motivate and direct the car exactly where I want it to go in its development, alongside a great teammate and fighting against a great team in Ferrari with the highest decorated, or was the highest decorated driver in the sport -- we are now both -- was a massive challenge I was looking forward to."

Dealing with that challenge is what Hamilton also claims makes this year one of the most enjoyable, however, with the whole Brackley operation focusing on a single goal.

"It's great to have two teams fighting,” he stated. “You could see through practice [in Mexico], us all within a tenth, the top six or whatever. I think that's great, we need more of that. It pushes us all more to the limit, it pushes the cars more to the limit and that's ultimately what has got us excited for the sport.

"We've all loved that challenge. Every single individual in the team has really raised their game. You go to the factory and I'm like 'why are you still here at 7 pm or 8 pm?' Sometimes it's later. They are like 'I've got a championship to win'. That hasn't come so easy."

Vettel too has been reflecting on the journey his 2017 season took and, though he downplayed their significance at the time, has now admitted the two retirements in Singapore and Japan were the defining moments in making Hamilton's title win easier than it should have been.

“In the end, you have 20 races, we’ve had 18 so far,” he said. “I’m not a big fan of pointing fingers in one race but we had two races that we didn’t finish and Lewis won both of them. They were the most costly.

“It’s normal you have the feeling here and there that you could have got a bit more but it doesn’t change anything now.”

His defeat this year ends the stat the German held of winning every championship in F1 that he has led at some stage, nevertheless, he vows to continue pushing until the end of what is still an excellent year for Ferrari.

“We will try to finish the season the way the team deserves and the car deserves,” he said. “In Mexico, we’ve been quick. I’m pretty sure we’ll get a result and that is the target for the next two races."