Daniel Ricciardo led a Red Bull one-two in FP1 ahead of the Singapore Grand Prix, while Ferrari-bound Charles Leclerc crashed in the closing minutes of the session.
With FP1 taking place in unrepresentative daylight conditions, the final timesheet was skewed by teams running alternate programmes.
Red Bull and Ferrari both opted to run the hypersoft tyre during the session, while Mercedes figured lower down on the timesheet as Lewis Hamilton and Valtteri Bottas instead set their fastest times on the soft compound.
Ricciardo ended up topping the timesheet, finishing 0.201 seconds clear of his team-mate Max Verstappen. Ricciardo’s benchmark time was set despite early session complaints regarding poor drivability.
Behind the two Red Bulls, Sebastian Vettel finished third and Kimi Raikkonen ended FP1 in fourth.
Raikkonen was one of a number of drivers to suffer brief excursions in the session, as he locked-up at Turn 18 taking to the escape road.
Charles Leclerc, Raikkonen’s recently announced replacement at Ferrari in 2019, made the most costly misjudgement in the session. He clipped the corner of the barrier at the end of the Anderson Bridge, tearing the right-front wheel off of his Sauber with three minutes of the session remaining.
Leclerc managed to recover to an escape road and the session was free of red flag intervention. He finished the session in ninth and was more than 0.3s clear of team-mate Marcus Ericsson.
The Renault pair of Nico Hulkenberg and Carlos Sainz Jr split the Mercedes on the timesheet in fifth and seventh respectively.
Hamilton in sixth and Bottas in eighth both suffered off-track moments during the session as they worked primarily on race setup.
Hamilton took to the run-off area at Turn 1 and Bottas needed to loop his Mercedes around in the escape road at Turn 14. This error followed an earlier half-spin for Bottas after having lost control on the kerb at Turn 2.
Sergio Perez and Lance Stroll also suffered spins during the session, with the street surface providing low grip early on.
McLaren’s Stoffel Vandoorne ended FP1 at the bottom of the timesheet. After experimenting with a new floor as part of set-up changes, his session was curtailed by a hydraulic pressure issue late on.