Fernando Alonso still believes he can win a third World Championship despite the struggles faced by his McLaren-Honda team.
The Spaniard, 34, won his second title in 2006 with Renault and has come close three times since - in 2007 with McLaren and 2010 and 2012 with Ferrari.
Asked on Spanish radio if he thought he could be champion again, he said: "Yes, I think so.
"I compete to win. If there was no chance, I wouldn't do it."
McLaren racing director Eric Boullier has predicted the team will make "massive progress" in 2016.
Alonso, whose best result last year was fifth place in Hungary, said: "I do not think we are far from achieving a podium.
"I would be surprised if we managed it at the start of the season, because in the first few races not everything will be in place."
He said his feelings for the 2016 car were "good", adding: "When everything is in place, we will make a very big improvements."
But he said Mercedes are still ahead of everyone else.
Asked about the Honda engine's performance compared to that of Mercedes, the Spaniard said: "We will certainly have less power, between 30 and 80bhp, but not 200, no."
Alonso said he had "never considered either retiring or taking a year out", adding that this was "unthinkable".
This is a direct contradiction of remarks by McLaren chairman Ron Dennis, who said at the final race of last season that the idea of a sabbatical for Alonso had been discussed at one point in 2015.
Alonso believes McLaren are the only team who could ultimately beat Mercedes but said: "We are starting a project and we are still some way off."
He said he had "never regretted" leaving Ferrari at the end of 2014, despite the team's upturn in fortunes.
Alonso's replacement, four-time world champion Sebastian Vettel, won three races in 2015 to finish third in the standings.
"I was offered to renew until 2019 and did not want to take it up," said Alonso. "I would never have been world champion there. Now I enjoy Formula 1 more being 10 positions further behind."