Mercedes have power issue to address in Mexico - Wolff
Toto Wolff concedes Mercedes will have to solve a power issue as Lewis Hamilton aims to secure the Formula One World Championship at the Mexican Grand Prix.
Briton Hamilton only needs to finish seventh at the Mexico City circuit to win a fifth world title, but Mercedes started the weekend off the pace.
Hamilton could only post the fifth fastest time in FP1, one spot ahead of his team-mate Valtteri Bottas, with Red Bull duo Max Verstappen and Daniel Ricciardo leading the way.
Indeed Renault-powered engines thrived on Friday, with Carlos Sainz Jr and Nico Hulkenberg rounding out the top four in the first session, while Ferrari's Sebastian Vettel - who hopes to once again prolong Hamilton's seemingly inevitable wait for glory – was down in seventh.
Speaking to Sky Sports after the end of FP1, Mercedes chief Wolff admitted there are problems to address.
"The altitude is totally different here," he said. "You can see that it is lacking power.
"Renault seem to be in good shape in the first free practice so it will be interesting to see where they are.
"It was like this in the past years and I think the Red Bull with the Renault have made a step forward."
It was a similar story in FP2, with Verstappen - the race winner in Mexico a year ago - going quickest with a time of one minute and 16.720 seconds ahead of Ricciardo.
Sainz and Hulkenberg were split by Vettel, while Hamilton once again showed Mercedes have work to do by posting the seventh quickest time.