Red Bull chief Christian Horner underscored once again the "mind-boggling" straight-line speed of Mercedes' W12 after Valtteri Bottas' win and Lewis Hamilton charge to P5 in Saturday's sprint event at Interlagos.
Bottas was able to fend off Max Verstappen in the 24-lap mad dash thanks to a lightening start and a well-managed soft tyre strategy.
But Horner was especially impressed with Hamilton's charge from last on the grid to fifth during which the Briton, thanks to his top velocity, was in "a different league".
"Lewis' straight-line speed is just mind-boggling," Horner told Sky F1.
"We've seen this coming for a few races now. Turkey, it started to be there. In Mexico, we saw the straight-line speed, I think they were about 14 km/h quicker at the end of the straight than we were, so it's no great surprise.
"We saw yesterday that it's phenomenal, especially with the size of the rear wing that they have on the car."
Horner hinted at a potential ploy exploited by Mercedes to blast down the straights and suggested that Red Bull had perhaps a few theories, confirming also that the team's CTO Adrian Newey had visited the stewards at Interlagos to discuss Mercedes' top speed advantage.
"It's something that is enabling the car to do that kind of speed," he said. "Something must happen, because physics wouldn't allow....
"The kind of horsepower delta that you would need to achieve that, would be pretty significant. So we're obviously trying to understand what it is and go from there."
When Sky F1 asked Verstappen what it was that he was looking at when he illicitly approached and touched Hamilton's car in parc fermé on Friday, the Dutchman also hinted at something going on with the Mercedes W12's rear wing.
"Well, I was clearly looking at the wing," admitted Verstappen. "So, yeah, I mean, you can see on the video what I did exactly. I was just looking at how much the rear wing was flexing at that point."
The Dutchman isn't discarding a flexing phenomenon taking place, despite the introduction in France earlier this season by the FIA of new anti-flexing load tests.
"Yeah, of course there have been talks, and of course there are things to still look into – because at a certain speed it seems like the wing is flexing," he said.
"Of course you know we had, at the beginning of the season, to all change the rear wings a bit because of the back off [of the rear wing at high speed].
"But it seems like something is still backing off over there [at Mercedes]. So, that’s why I went and had a look."
Regardless of how Mercedes is generating its superior velocity, Horner insisted that it's the FIA's responsibility to keep teams honest.
"It's down to the FIA to police. The rules are quite concise, they're ever more constricted," he said.
"It's something that we're going to keep an eye on because, particularly with Lewis today, that was just a different league.
"I think he was 27 km/h faster than Lando [Norris] when he passed him, which is another formula, but it's a great drive from him."
Gallery: The beautiful wives and girlfriends of F1 drivers
Keep up to date with all the F1 news via Facebook and Twitter
The opening day of running at the Las Vegas GP was a smooth but chilly…
Williams is continuing to fight uphill battles this weekend in Las Vegas as a knock-on…
It was a solid start to the Las Vegas weekend for Ferrari with Carlos Sainz…
Lando Norris didn’t hold back in his assessment of McLaren’s performance on the opening day…
Lewis Hamilton was particularly happy with his opening day of running at the Las Vegas…
Red Bull fears that its prospects for this weekend's Las Vegas Grand Prix - which…