If Renault can continue to improve its power unit at its current rate, Red Bull chief technical officer Adrian Newey believes it will not be long before its starts to level up with Mercedes.

Renault initially struggled when the current turbo engine regulations were introduced in 2014 and Red Bull publically criticised the French manufacturer when it failed to make progress in 2015. However, work over the winter and an upgrade at this year's Monaco Grand Prix have seen Red Bull return to the front of the grid and Newey has been impressed by the engine supplier's progress.

"I think it's fairly well recorded that at the start of last season there was a frustrating time when Renault if anything, frankly, were going backwards rather than forwards," he said. "But they seem to have really gone away, understood their problems and made really good progress over the last winter and again with the upgrade that we had for Monaco. If they can keep that ramp going then we can really start to close in power unit wise on Mercedes."

Red Bull took its first victory in over 18 months at the Spanish Grand Prix this year and Newey said a large part of that was down to Renault's improvement.

"It's obviously good to have won a race again this year. Monaco was frustrating because we mucked that up ourselves, but to be back running at least somewhere near the front is a reward to not only all the hard work that's gone on at Red Bull, but also all the hard work Renault has put in over the last 12 months."