The team will revert to Renault's previous specification power unit for this weekend's Abu Dhabi Grand Prix despite using the upgraded version in Ricciardo's car in Brazil a fortnight ago.

Although there has still been no official announcement, Red Bull is expected to continue with Renault next season despite its earlier attempts to extricate itself from its contract when it believed it could get Mercedes engines instead.

Asked how much confidence he had in what Renault was doing given his disparaging view of the latest upgrade in Brazil, Ricciardo replied: "It's definitely obvious they've got some work ahead of them.

"We put in the D-spec, or whatever, in Brazil and it didn't really show a whole lot.

"There would need to be a change of direction."

But though he remains critical of Renault's performance, Ricciardo thinks Red Bull has made great strides with its chassis.

"If we had more power, we could probably win races," he said.

"We didn't have the quickest car at the start of the year. The chassis had some deficiencies.

"But I think what the team's done has made the chassis back to pretty much what it was last year, which was as good as the Merc."

Red Bull has yet to formally confirm it will stay in F1 for 2016 after earlier threats to leave over its engine situation, but has gone through the first stage of the entry process and announced numerous sponsor deals for next year.

Ricciardo said the team had continued to reassure its drivers.

"They're just saying we're working on it, we will have something, so don't stress," said Ricciardo.

"Obviously there's a bit of weight off, knowing that we will be on the grid, but it would be nice to know how competitive we think we'll be."