Felipe Massa has imposed a looming deadline for Formula 1 and its governing FIA to react to his threat of legal action.
The former Ferrari driver's lawyers recently sent a letter to the sport's authorities alleging their inaction in 2008 cost him the world championship over the 'crashgate' affair.
Now 42, the legal action was triggered by recent comments by former F1 supremo Bernie Ecclestone, although the 92-year-old Briton claims he doesn't remember making the comments.
But Massa is also relying on never-released footage of the late former race director Charlie Whiting, who presumably made similar comments about knowing about the deliberate crash before the 2008 season had ended.
According to the Associated Press, F1 and the FIA responded to Brazilian Massa's first letter by asking for more time, given that so many staff members have been on vacation for the summer break.
Massa's lawyers have now replied, rejecting the argument and giving Formula 1's authorities only until the end of the week to satisfactorily respond.
In the new letter, Massa's lawyers claim the two F1 bodies "deliberately ignored the misconduct (at the 2008 Singapore GP) which deprived him of this title".
When asked about the threat of legal action, Massa told AP that he is "100 ready" to take the matter to court.
"I trust and I really believe that for justice, we will show that what happened is not right," he said.
"I am the champion and I feel it. I feel like I have that title. I am the 16th Formula 1 champion for Ferrari," Massa insisted when asked about the new letter.
"I lost my peace of mind because I knew I was robbed," he added.
Massa revealed that F1's authorities asked him not to attend this weekend's Italian GP at Monza.
"We decided not to go there," he said, "but it doesn't change anything in our battle.
"F1 today is different from F1 then and the FIA is different today than it was then," Massa added. "I really hope they understand that what happened is not fair and that they will settle the matter."
