Lewis Hamilton, winner of a record 103 Formula One grands prix and seven world championships, said on Sunday he had never seen a car as quick as Max Verstappen's Red Bull.
The Mercedes driver was overtaken by the double world champion as Verstappen powered from 15th on the grid to second in a Saudi Arabian Grand Prix won by Red Bull's Mexican Sergio Perez.
It was Red Bull's second one-two in two races this season and the only point they have missed so far was the bonus for fastest lap in Bahrain.
"I’ve definitely never seen a car so fast," Hamilton told reporters after finishing fifth in Jeddah.
"When we were fast, we weren’t that fast.
"That’s the fastest car I think, I’ve seen, especially compared to the rest. I don’t know how or why but he came past me with serious speed.
"I didn’t even bother to block because there was a massive speed difference."
Before the race, Hamilton reckoned Red Bull enjoyed a one and a half second advantage per lap.
Hamilton's teammate George Russell, who finished third after Aston Martin's Fernando Alonso was demoted from the podium by a 10-second post-race penalty, said already in Bahrain that he could see Red Bull winning every race.
"You’ve got to give credit to what Red Bull have done," the Briton said on Sunday.
"The gap they have to the rest of the field, I think is bigger than we’ve seen probably since Mercedes in 2014. It’s a serious, serious gap and I guess everybody needs to keep working harder to understand how to close that gap.
"But we know we didn't make the right decisions over the winter and I think we can regain some of that performance quicker than you would do ordinarily. So everything's not all lost."
Mercedes won eight constructors' titles in a row from 2014 until Red Bull dethroned them last year.
Hamilton, who made his F1 debut with McLaren in 2007, has won six of his titles with Mercedes.