McLaren's pace during qualifying, for the 2023 British Grand Prix, is another wake-up call for Mercedes as they struggle for performance warns local hero Lewis Hamilton.
The seven-time Formula 1 World Champions sounded the warning to his team after another below-par session for a driver that has started P1 on 103 occasions, but not this Sunday.
Lando Norris qualified a stunning second and rookie teammate Oscar Piastri third, in a revised car and on a drying Silverstone track, with Mercedes's George Russell and Hamilton only good for sixth and seventh.
A former McLaren driver himself, Hamilton said after qualy: "If you just put it (the McLaren) alongside a Red Bull, it looks very, very similar down the sides. It's working. It is great."
Asked if being beaten by different customer teams, Aston Martin at first and now McLaren, was a blow to Mercedes, Hamilton replied: "It's not a blow. It’s just a wake-up call for us all that others are overtaking us and we need to do more."
Mercedes are second in the championship, but 199 points behind Red Bull, and are struggling to beat teams using the German manufacturer's engines. Merc-powered Aston Martin were the revelation of the early rounds, with Fernando Alonso standing on the podium six times in nine races, and they remain only three points behind.
Mercedes enduring their worst spell in F1 since they returned in 2010
McLaren, with their heavily upgraded Mercedes-powered car, could provide similar shocks. Similarly Merc-powered Williams also appear to be waking up from their long slumber with Alex Albon quick in practice and qualifying a competitive eighth.
"It seems like they have made a massive step in understanding and performance," Mercedes team boss Toto Wolff said of McLaren's new-found form after Norris finished fourth in Austria last weekend, with Russell seventh and Hamilton eighth. But the jury remained out amid suggestions that result was track specific given McLaren's strong past form there.
Silverstone may have forced a rethink of that theory, and garnered praise from Woilff "I think it's very encouraging to see that Aston Martin found massive chunks of lap times from last year to this year and in the same way you see that within the season McLaren doing that. You need to take your hat off if we see that consolidating, and certainly for us a good example of how you can turn around things."
Asked about Hamilton's "wake-up call" comments, Wolff replied: "From what you see, from the outside which is obviously only half the information, is that the car looks like a Red Bull. To be honest it doesn't matter because only the stopwatch counts. This is what I guess Lewis was referring to. That this kind of design seems to be a good direction.
"But this is easier said than done. Each of us had bodyworks that looked like a Red Bull in the tunnel and it didn't come up in performance. So we've got to maybe look at it again because another team just found a second in performance," lamented Wolff.