Red Bull Team Principal Christian Horner believes Mercedes had "a stroke of luck" with the timing of red flags in the Mexico City Grand Prix.
Lewis Hamilton finished second for the Silver Arrows having made his way through the top five, though still wound up almost 14 seconds adrift of race winner Max Verstappen.
The seven-time World Champion was third after pitting early to switch to a set of Hard tyres but was thrown a strategic lifeline when Kevin Magnussen's Haas crashed out midway through the race to trigger a stoppage, with the barriers in need of repair.
This allowed Hamilton to switch tyres without stopping again, before overtaking Charles Leclerc's Ferrari four laps after the restart.
Judging Mercedes' race as Hamilton again closed on Sergio Perez's second in the Drivers' standings, Horner told Viaplay: “They had a bit of a stroke of luck because they went in very early for a one-stop strategy,” he told Viaplay. “I think in the end they would have been beaten by the Ferraris.
“But it is true that they had good speed and did well in terms of tyre wear, as we have seen from them all year.”
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Hamilton had pushed Verstappen close at the United States Grand Prix before being thrown out of the race for illegal skid block wear, though the performances so far in the triple-header will provide Mercedes with optimism going into the São Paulo Grand Prix.
The Brackley-based outfit has won the last two renewals of the event and asked if more competition could be expected at Interlagos, Horner told media including RacingNews365.com: "They were competitive on race runs and Austin is difficult to judge because of what happened.
"But we expect them to be competitive in Brazil, for sure.
"For us, it is an itch unscratched from last year where we feel we didn't quite get the set-up right, so we will try and go and put that right this year."