Michael Schumacher will head into the last race of the season believing he can snatch the title from Renault's Fernando Alonso, says Damon Hill.
Michael's going to go into that last race thinking: 'Now, how can I win this and Alonso not score anything?'
The German, who to become champion must win in Brazil on 22 October with Alonso not scoring, conceded his hopes after retiring in Japan on Sunday.
But Hill said: "Michael said he's not thinking about the championship now. That's baloney. He never gives up.
"I would keep my armour on if I were Alonso until after the last race."
Speaking to BBC Sport, Hill said Schumacher would be exploring every avenue in his attempt to win the title.
"Don't ever write that guy off. It's not over 'til it's over," said the 46-year-old Englishman, a former arch-rival of Schumacher.
"He's going to go into that last race thinking: 'Now, how can I win this and Alonso not score anything?' That's the way he's going to approach it. Otherwise, he's not Michael Schumacher."
Renault engineering director Pat Symonds agreed, saying: "I am sure Michael will be racing just as hard."
Schumacher conceded the title after retiring in Japan
"He might be playing down his chances, but it is still possible for him."
Symonds, who knows Schumacher well after working with the German when he won his first two titles with Benetton, said Alonso's victory at Suzuka "doesn't change a thing".
He said it was important for Renault to "acknowledge the fact" that they can still lose the drivers' championship.
"As always, our strategy for Brazil will be grounded in solid reliability, and giving ourselves the tools to finish races.
"We are in a position where we do not need to take undue risks."
Symonds echoed Alonso's belief that the Spaniard's victory in Japan was long overdue after a sequence of errors and other incidents allowed Schumacher to close a 25-point gap to nothing since June.
The win feels like a reward for the disappointment of the past two months
Renault engineering director
Symonds said the win was "particularly satisfying".
"Ever since Hungary two months ago, we have been threatening to win again, and it has been frustrating for the whole team that it hasn't happened.
"That makes the win particularly sweet. Of course, it comes at a critical time of the championship, but it certainly feels like a reward for the disappointment of the past two months."
And he said that Schumacher's engine failure had robbed the race of a thrilling fight between the two drivers in the closing laps.
"Fernando seemed to be catching Michael quite convincingly in that middle stint," he said, "and the projection was that he would have caught him - but the performance differential between the two cars would probably not have been enough to overtake on a circuit like Suzuka.
Alonso bounced back from a long barren spell to win at Suzuka
"I think Michael's failure probably robbed us of a classic Alonso-Schumacher battle in the closing laps."
The constructors' championship is also still open, with Renault leading Ferrari by nine points after Ferrari's Felipe Massa finished second ahead of Alonso's team-mate Giancarlo Fisichella.