Red Bull 2015 hopes raised by US Grand Prix podium

Despite the long straights of Austin, Ricciardo was able to overcome the more powerful Williams cars to emerge as best-of-the-rest behind Mercedes.

With Red Bull believing that its horsepower deficit was as high as one second per lap, it thinks a step in performance from Renault over the winter could be enough to lift it on a par with the currently dominant Mercedes team.

"I think when you look at the deficit in power, to be actually taking on and beating Williams is impressive," said Red Bull boss Christian Horner.

"It is about one second that we are giving away in horsepower at the moment.

"So if we can just find some of that deficit, even halve it, then we should be able to put the pressure on a little bit more to Mercedes."

Although Ricciardo's podium finish was not enough to keep him in the drivers' championship, Horner says the team still wants to push hard for the remaining races to ensure second place in the constructors' battle.

"It is a straight race between now and the end of Abu Dhabi," he said. "We still have to finish the job off on the constructors' championship.

"I think we are a couple of points shy from tying up second place now.

"But obviously we want to try to finish the season off on a high. Both drivers did an exceptional job in America.

"But for Daniel in particular after a poor start, his race was mightily impressive."