Lewis Hamilton believes that a fundamental lack of downforce was the main reason for the significant gap between himself and title rival Max Verstappen during Friday practice for the Mexican Grand Prix.
Mercedes started the weekend with a 1-2 in first practice at the Autodromo Hermanos Rodriguez, but Verstappen and Red Bull surged ahead in FP2, finishing four-tenths clear of Valtteri Bottas, and a further tenth up on Hamilton.
Hamilton was a match for Verstappen in Sector 1, where straight-line speed is key, but significantly slower through the more technical Sector 2 and Sector 3.
Red Bull had been tipped as favourites for Mexico and Brazil, given the high altitudes and the subsequent effect on engines, and Hamilton admits they will be tough to beat as the weekend develops.
"We're giving it absolutely everything we've got," said Hamilton after Friday's pair of sessions. "I think they're [Red Bull] just quicker than us at the moment.
"I've got no real concerns. [We're] just chipping away at our setup and just trying to improve it. But we're lacking downforce which is definitely, [or] probably why we have the half-second difference between us."
He added: "It's looking good for us to be able to try and battle with these guys, but they're definitely too quick for us at the moment."
Hamilton currently trails Verstappen by 12 points in the standings.
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