Red Bull's Max Verstappen lapped fastest in opening practice for the Singapore Formula One Grand Prix on Friday with Ferrari's Sebastian Vettel close behind.
The Dutchman set a benchmark time of one minute, 40.259 seconds over the first of the day’s two 90-minute sessions. Vettel, a four-time winner at the twisting Marina Bay track, was 0.167 seconds adrift.
Championship leader Lewis Hamilton was third for Mercedes, 0.666 seconds off the pace.
The Briton, who leads team mate Valtteri Bottas by 63 points with seven races to go, is also a four-times winner in Singapore.
Hamilton is looking to return Mercedes to the top of the podium after two successive defeats to Ferrari in Belgium and Italy.
Bottas was fourth, but the Finn crashed out with a little under half an hour left on the clock when his Mercedes snapped out of control on the exit of turn 19 and ploughed into the barriers.
The accident brought the session to a brief halt as marshals worked to clear away his car.
Alexander Albon, in only his third race for Red Bull after switching from Toro Rosso, was fifth fastest on what is almost home territory for the British-born Thai rookie.
Nico Hulkenberg, out of a drive for next season, was sixth for Renault ahead of McLaren pair Carlos Sainz and Lando Norris.
Daniil Kvyat was ninth for Toro Rosso ahead of French team mate Pierre Gasly who rounded out the top 10.
Charles Leclerc, winner for Ferrari in Spa and the team’s home race at Monza, was only 19th. The Monegasque spent much of the session in the garage with gearbox problems.
Friday's opening daylight session was unrepresentative of the rest of the weekend’s action, including qualifying and the race which take place at night under the floodlights.
Red Bull have finished second in Singapore for the last five years.
Verstappen, already a double winner this season and runner up to Hamilton in Singapore last year, is aiming to go one better on Sunday.
Just R20 for the first month. Support independent journalism by subscribing to our digital news package. 