Christian Horner believes it is "remarkable" that Mercedes got the new 2022 technical regulations wrong to the extent they have.
Mercedes entered the season as eight-time consecutive Constructors' champions, having transitioned through rule changes in 2017, '19 and '21 to keep their win streak going in the turbo-hybrid era.
However, for 2022, sweeping new technical regulations were introduced that brought ground-effect cars back into F1, with the known side-effect of porpoising becoming apparent in pre-season testing.
Mercedes were badly hampered by the bouncing and struggled in the early races. Although there have been strong recovery signs, the team is yet to record a Grand Prix victory this season, with just six races remaining to prevent a first winless campaign since 2011.
Horner, whose Red Bull squad are set to win the championship double for the first time since 2013, says he shocked by the fall-off in performance from the Brackley squad.
Horner "shocked" that Mercedes yet to win
"Yes [I am surprised by Mercedes' lack of pace]," Horner explained on the F1: Beyond the Grid podcast.
"Because they transitioned early [to the 2022 rules in '21], they made quite a noise about compromising last year's championship and moving over very early on to onto their 2022 car.
"Then, of course, when their car broke cover, particularly with this [zero sidepod] upgrade, it looks so radically different.
"You just have the expectation, from seeing how dominant Mercedes have been, that they would be in a very similar position.
"Obviously [they were] hurt last year getting beat [to the Drivers' title by Max Verstappen] but we felt that they would come back with a renewed vengeance for this year.
"So, it is quite remarkable that after the domination that they've had for the last eight years, that they're yet to win a Grand Prix in 2022 [prior to the Singapore Grand Prix]."
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Horner on legality of Mercedes' 'zero sidepod' concept
The Mercedes W13 has a unique sidepod design philosophy, opting for a much thinner design (often described as "size zero"), while Ferrari and Horner's Red Bull squad have gone for more conventional, wider designs.
Upon seeing the design for the first time at the second pre-season test in Bahrain, Horner admitted his first thought was whether it was in line with the regulations.
"The first question was: 'Is it legal?'," he explained.
"Because it's a very different interpretation, and of course, it was.
"Then the guys were pretty convinced early on that they just didn't feel that it would work within the architecture that we created.
"There was an inner confidence that we'd picked the right route.
"When the lap times started to come in from that Bahrain test, and you could visibly see the cars on track, it didn't look like that they had a rocket ship, or that we'd missed something fundamental."
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