F1 championship leader Vettel wants Red Bull in fight at front

Red Bull is working on a radical overhaul of its RB13 to help bring much needed downforce, having initially focused on producing a low-drag car only to trail the top two teams in the opening races.

Vettel, who won his four F1 championships so far with Red Bull in 2010-13 during a six-year stint in the team, expects the traditional flurry of updates for the start of the European season at Barcelona to reset the pecking oder.

"I think it will be a very close race between Mercedes and us, I hope, and I also hope that Red Bull find some pace," said Vettel after finishing second in a Russian GP dominated again by Mercedes and Ferrari.

"There's a lot of rumours around [regarding the Red Bull update].

"They are a strong team, they know how to build a quick car so I expect it's a question of when rather than if.

"But the sooner, the more exciting it will be for us.

"I'm confident that we have the right people, the right tools on board and we will make progress.

"It obviously depends on what others are doing."

So far Daniel Ricciardo and Max Verstappen have been unable to properly challenge Ferrari and Mercedes for leading positions in 2017, with Verstappen's third place in China Red Bull's only podium of the year.

Red Bull boss Christian Horner admitted that his team's situation was not an easy one, but is optimistic Barcelona will be the turning point.

"We've given ourselves a lot to do but the whole team is focused on that and hopefully for the next race, we can start making progress," he said.