Red Bull believe that Mercedes could be set to make it a three-team fight for victory at this weekend's British Grand Prix.
Having swept every title bar one since 2014, Mercedes have slipped back in competitiveness in 2022, as Ferrari and Red Bull have shared all eight Grand Prix wins so far this year.
But Mercedes put on arguably their most competitive showing of the season so far at the Canadian Grand Prix, as Lewis Hamilton and George Russell finished a solid third and fourth.
Hamilton in third was only seven seconds adrift of race winner Max Verstappen by the chequered flag, and the Briton cut a noticeably happier figure than he had been after the previous race in Baku, when his W13 had struggled badly with porpoising and Hamilton appeared to be in pain as he lifted himself from his cockpit.
Speaking to media including RacingNews365.com, Red Bull Team Principal Christian Horner expressed concerns that upcoming circuits on the 2022 F1 calendar would continue to play to Mercedes' strengths.
"I think Mercedes will be strong at Silverstone and I don't see any reason why they wouldn't be at Paul Ricard," said Horner.
"I think Ferrari will be quick at Silverstone as well. It could be more of a challenging circuit for us, just due to the nature of its layout.
"It's incredible that we've put a run of six race victories together, but Silverstone could well be the most challenging yet."
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Marko also wary of Mercedes pace
Red Bull's Special Advisor Helmut Marko echoed Horner's worries, with the Austrian referencing Mercedes' competitive pace at Montreal.
"Mercedes were very strong on Sunday in Canada. At times, they were even faster than us. And Silverstone, I think this circuit suits them better," Marko told Austria's ORF.
Hamilton has won seven of the last eight British Grands Prix, notably winning 2021's event despite receiving a penalty for a controversial Lap 1 tangle with Verstappen that sent the Dutchman into the barriers at high speed and out of the race.
F1 Podcast: What's next in F1's porpoising row?
RacingNews365.com F1 journalists Dieter Rencken and Michael Butterworth discuss the key topics from the Canadian Grand Prix, including the fierce debate over the FIA's intervention on porpoising.