Red Bull may need to change parts on Max Verstappen's power unit ahead of the Hungarian GP on Sunday.

"It was a mechanical problem," said Dr Helmut Marko, after Verstappen qualified just tenth at the circuit near Budapest on Saturday.

"In his second run he didn't have the full engine power at his disposal," he explained. "We think we know what it is.

"The exchange of this part is possible without penalty. But a result like this here or in Singapore or Monte Carlo is exactly where you don't want it."

It was also a difficult qualifying for Ferrari, with Mercedes' George Russell securing a surprise pole position.

"I don't know, to be honest," said the British driver when asked where his pace suddenly came from.

"We need to look into it and understand where that came from today."

Mercedes boss Toto Wolff is also not getting overly excited, as he admitted that the Brackley based team is zipping from "enthusiasm to depression" race by race.

"If the race turns out to be the best part of the weekend for us as usual, then maybe we can say we have turned the tide," he said.

The good news for Verstappen's main title rival Charles Leclerc is that while he may be starting third behind Ferrari teammate Carlos Sainz, Verstappen is a lot further back.

"It might take Max a few more laps to come back to the front but we'll just focus on ourselves and try to win the race," said Leclerc, who is 63 points behind Verstappen.

Marko said of Verstappen's prospects: "I think a podium is unrealistic."