Red Bull has struggled so far in 2015, having scored only 23 points in the first four races and sitting a distant fourth in the constructors' standings.

The Milton Keynes-based team lost its quadruple world champion Vettel to Ferrari over the winter, but team adviser Marko believes that Ricciardo, who won three grands prix for the team during a standout 2014 campaign, has shown he is of a similar calibre.

"Our relationship with Sebastian was built up over many years, but that does not mean we are left with nothing," said the Austrian according to Germany's Auto Bild.

"Daniel showed last year that he is on the same level in terms of speed and car development."

Red Bull replaced Vettel with Daniil Kvyat, but the 20-year-old Russian, who made the step up after just one season driving for Toro Rosso, has endured a tough start to the year.

"Sebastian had a lot more experience, but Daniil has learned quickly to understand the technical aspects," said Ricciardo.

"I think he just needs a decent weekend to begin to show his full potential, but we are working well together to help the team."