MEXICO CITY -- Valtteri Bottas beat Mercedes teammate Lewis Hamilton by 0.4s as the newly-crowned world champions made a strong start to the Mexican Grand Prix weekend.
Though Hamilton can wrap up the drivers' title by finishing fifth or higher this weekend, it was Bottas who topped Friday morning's session. It will be a boost to the out-of-form Finn, who has struggled for pace at the last few races. Mercedes wrapped up the constructors' championship in Austin but is braced for a more difficult weekend at the Autodromo Hermanos Rodrigeuz.
As with most FP1 sessions of a grand prix weekend, the lead times are likely to be misleading at this stage -- while Bottas and Hamilton set their quickest laps on the ultra-soft tyre, Red Bull and Ferrari's were set on the slightly harder super-soft tyre.
Red Bull finished third and fourth, with Verstappen's quickest time on the super-softs just over 0.1s slower than Hamilton's best attempt on the ultra-soft. Though the Mexico City circuit has a punishing long straight, its twisty and technical second and third sectors are likely to suit the former world champions' aerodynamic prowess.
Ferrari settled for fifth and sixth, though Sebastian Vettel's deficit of 0.7s to the lead is unlikely to continue into the more meaningful sessions of the weekend. Kimi Raikkonen finished 0.4s off his teammate's quickest effort.
Away from the top six, local favourite Sergio Perez finished as best of the rest. Force India ran an all-Mexican line-up for the morning session, with Alfonso Celis taking Esteban Ocon's seat for FP1. However, Celis had a session to forget in front of his home crowd, slamming into the wall at Turn 16 after losing the rear of his car on the run into the corner.
Fernando Alonso, who already has a 20-place grid penalty for Honda engine changes, was eighth, ahead of Williams' Felipe Massa. Renault teammates Nico Hulkenberg and Carlos Sainz were split by just 0.02s in 10th and 11th.
Lance Stroll finished 11th for Williams in what appeared to be a frustrating session for the teenager. The Canadian was hampered by traffic on one of his hot laps and then complained to his pit wall that he was out of sync with the high-fuel runners in the closing portion of FP1.
Haas driver Kevin Magnussen was 13th in a session in which the team was running split aero packages between its cars, with Antonio Giovinazzi standing in for Romain Grosjean. Haas is continuing to evaluate the upgrade package introduced in Austin.
Pascal Wehrlein split the Haas drivers with an impressive run to 14th. Behind Giovinazzi, fellow Ferrari junior driver Charles Leclerc was 15th in the other Sauber, narrowly ahead of Toro Rosso pair Sean Gelael -- who spun mid-way through the session -- and Brendon Hartley, who's car appeared to be suffering from engine issues after he slowed during the opening 30 minutes
Behind Celis in the standings was Stoffel Vandoorne, who failed to set a time in his McLaren after the team detected a power unit issue after just three laps. The team switched back to an old power unit, meaning the issue won't add to the 35-place penalty he is already set to serve for changes made to his Honda power unit ahead of the session.