Ferrari's Charles Leclerc topped the time charts in the opening practice session for the Russian Grand Prix.
Leclerc edged out Red Bull driver Max Verstappen by just 0.082 seconds at the Sochi Autodrome.
Lewis Hamilton, who holds a 65-point championship lead heading into the final six rounds, finished fifth.
Great job from the team in #FP1 💪Results ⬇️ #Charles16 🇲🇨 P1#Seb5 🇩🇪 P3No time for relaxing. We've got another 90 mins of #F1 action later today. #essereFerrari 🔴 #RussianGP Posted by Scuderia Ferrari on Friday, September 27, 2019
Ferrari have been the team to beat since the summer break, with Leclerc winning successive races in Belgium and Italy before team-mate Sebastian Vettel ended his 13-month losing streak with victory in Singapore last weekend.
Leclerc again led the way for the Scuderia here, with Vettel third, albeit half-a-second adrift of the German.
Hamilton's Mercedes team have won all of the five races staged in Russia since the fixture made its debut on the calendar in 2014, but the silver cars were only fourth and fifth in the first running.
Valtteri Bottas finished 0.736 seconds down on Leclerc while Hamilton was the best part of one second adrift.
First session at the @SochiAutodrom in the books 🏁 It ends with Valtteri in P4 and Lewis in P5. Time for some lunch 😋#RussianGP pic.twitter.com/6uw2ugJBw0 — Mercedes-AMG F1 (@MercedesAMGF1) September 27, 2019
Hamilton ran off the road at Turn 2 in the opening exchanges before complaining about his brakes.
His Mercedes mechanics made alterations to his car, but the British driver was unable to reduce the deficit to Leclerc at the summit of the standings.
Neither Hamilton nor Bottas posted a time on the quicker soft tyre, however, to suggest there will be more time to come from Mercedes in the day's concluding running.
Daniel Ricciardo broke his rear wing after a late crash. The Renault driver lost control of his car through the right-handed Turn 10 before sliding backwards into the barrier.
Ricciardo, who finished eighth, limped back to the pits.
Red Bull driver Alex Albon ended the running in fifth place, one second off the pace. British teenager Lando Norris finished 16th, 2.4 seconds off Leclerc's pace.
Home favourite Daniil Kvyat broke down on track after an apparent fuel issue in his Toro Rosso.
