Red Bull not expecting full Renault F1 engine upgrade until Canada

Considered by many the outfit most likely to take the fight to Mercedes with F1's new technical regulations, Red Bull was quiet during pre-season testing and then endured a tough season opener in Australia.

Max Verstappen was its lead qualifier in fifth place, 1.297 seconds off pole, and then finished the race in the same position behind both Ferrari and Mercedes drivers, 28.827s off winner Sebastian Vettel.

Red Bull motorsport advisor Helmut Marko says his outfit is expecting a Renault upgrade at the Spanish Grand Prix in May, and then a bigger step in Montreal a month later, but concedes its RB13 also needs development.

"There's a lot of work to do," he told Autosport.

"The race speed makes us think positively. But from our side there is a lot to do, and Renault's side as well.

"Montreal is their biggest step. Something smaller is coming in Barcelona, but a reasonable step in Montreal."

Renault has reverted to its 2016-specification MGU-K for the start of the season, following persistent problems in testing.

Asked if the French manufacturer's upgrades would be enough to move Red Bull back into the fight with Ferrari and Mercedes, Marko said: "We hope so, if we improve our chassis dramatically as well.

"Our engineers think so, and the simulations say so also."

Team principal Christian Horner has played down the impact of 2017's ban of trick suspension systems on Red Bull's form, but agrees with Marko that its output is not purely shaped by Renault.

"It's difficult to say, but these things come as a package," Horner said, when asked how its deficit was split between chassis and engine.

"It's probably an equal share.

"I think [chassis development is] going to be incremental at every event.

"For sure it's going to keep our design office pretty busy."