Vettel is F1 title favourite - Red Bull chief

Sebastian Vettel is the favourite to win his fifth world drivers' title in 2018, according to Red Bull head honcho Dr Helmut Marko, who has also dismissed any suggestion that Ferrari are gaining an unfair advantage in Formula 1 with this year's car design.

Vettel won the opening two races of 2018, but has missed out at the last two grands prix - thanks to a collision with Max Verstappen in Shanghai and his failure to overtake Valtteri Bottas in Baku after being outdone at the safety car.

It leaves the German four points behind Lewis Hamilton - who won unexpectedly in Azerbaijan - although his three pole positions in a row suggest that Ferrari enjoy a greater level of performance than the Silver Arrows.

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Marko oversaw Vettel's four championship wins at Red Bull and he believes that number five is on the cards for the German this year.

"He is my world championship favourite," Marko told Sport Bild.

"Sebastian looks even more mature and balanced than he did last year. But also Ferrari has the better car. Now they have to not make any mistakes."

Some eyebrows have been raised over the legality of Ferrari's 2018 car, which has made a vast step forward in terms of pace - helping Vettel match the Mercedes pair in qualifying performance.

The sight of Ferraris - and Ferrari-powered Haas and Sauber cars - smoking while being started up has become a common sight, but Marko has seen nothing untoward.

"The FIA looks very closely, for example with the oil, and they say everything is correct," Marko said.

"There was speculation about the batteries and this too will be looked at by the FIA, but it didn't come from us.

"For us, the Ferrari is legal, because we trust the FIA."