Bernie Ecclestone on Friday said he is certain Max Mosley will step down as FIA president in October.
As part of the FOTA peace deal, 69-year-old Mosley pledged not to contest another election, but he was subsequently angered by the reaction of the breakaway group and said he was reconsidering his options.
"He said his options are open but he didn't say what they were going to be, did he?" Ecclestone, the F1 chief executive, said in a new interview for the Times, less than a week after controversially commenting about Adolf Hitler.
He explained that Mosley's threat to do a u-turn on his promised resignation was because he was "a bit upset" with Luca di Montezemolo's public reaction to his impending exit.
Ecclestone said at the Nurburgring: "I have no doubt in my mind (he will retire). As long as I've known Max, he's always done what he said he would do."
The 78-year-old was speaking amid rumours the FOTA teams and the owners of F1's commercial rights, CVC, have sidelined him in their latest negotiations over a new Concorde Agreement.
Late on Friday, Britain's Guardian newspaper said in a headline: "Formula one teams bypass discredited Ecclestone to seek 2010 resolution".