Senior figures from Red Bull, including owner Dietrich Mateschitz, have made repeated threats to pull both of its teams out of F1 if it cannot find competitive engines for Red Bull Racing and Toro Rosso.

Autosport understands Red Bull reopened talks with Renault over the Russian Grand Prix weekend, following what appeared to be a terminal breakdown in its relationship with the French manufacturer during a second tough season for the partnership.

Ecclestone admits he felt the possibility of Red Bull leaving was legitimate, but he believes the matter has now been resolved.

When asked if he thought Red Bull would pull out, Ecclestone told Autosport: “I think now, with what’s happened, no.

“But before, I thought yes.”

Asked to clarify what had happened to make him so confident, he added: “Things are sorted.”

Red Bull made clear over the summer it was keen to replace Renault with a more competitive engine supplier, but approaches to Mercedes and Ferrari were unsuccessful.

It had hoped a Mercedes engine could be badged by Aston Martin, but the deal was rejected by the German manufacturer at board level.

Meanwhile Toro Rosso is now in talks with Ferrari to land a supply of year-old power units for next season, a deal that should be made possible by teams’ unanimous support for a regulation change allowing manufacturers to offer different engine specifications.

Ecclestone also confirmed that Red Bull’s long-term commitment to F1 means contracts are in place that would prove costly to break.

“Look, if he [Mateschitz] says he’s leaving and he leaves, he knows it’s going to be very expensive,” he said.

He also added that smaller teams “who are complaining” about the terms of their own F1 deals couldn’t commit to deals including such penalty clauses.