Lewis Hamilton has insisted that he will not give up his fight to claim the Formula 1 world crown, despite heading into the final two races as the underdog.

The Mercedes driver has three championship titles under his belt, but he faces a tough battle to overhaul teammate Nico Rosberg, who currently has a 19-point lead over the Brit in the driver rankings.

Rosberg, who has had public spats with Hamilton in the past, showed intent early on in the season when he won the first four races of the campaign.

The German's teammate fought back to win six of the next eight Grands Prix, but an engine blowout during the Malaysian race forced Hamilton out of contention for a podium spot, and a disappointing start in Japan resulted in the 31-year-old finishing third.

Wins in the United States and Mexico, though, have given Hamilton a 13/5 chance of retaining the world title, according to online bookmaker 888sport, but Rosberg remains the 1/4 favourite to take home the crown, which will be his first ever championship triumph.

"It's a great feeling when you're able to show the kind of pace I've shown at the past two races," Hamilton told reporters. "Everyone has worked so hard and the car has really been faultless. The speed has been there all season, I just haven't always had the opportunity to take advantage of it.

"In terms of the championship, it's an unusual scenario to be in - fighting for something and not knowing for sure that what you do will guarantee you're able to make it. One outcome would be painful and the other would be a great achievement.

"Regardless, I'm going to keep pushing. Since the beginning of my Formula One career I've seen that everything can change even at the very last moment, so you have to fight to the bitter end. I've never won in Brazil, so I go into this weekend focused on changing that."

Should Rosberg triumph at the Brazilian Grand Prix this Sunday, then he will become champion with one race left on the calendar, and even if Hamilton wins the final two showdowns, his teammate will still take the title with second and third-place finishes.

Despite being on the back foot in the championship race, 888sport backs Hamilton 3/4 to win in Brazil, while the bookmaker has offered odds of 29/20 for Rosberg to seal the championship this weekend.