Red Bull and Ferrari set pace in Singapore practice

Verstappen posted a 1m41.829s on the ultra-soft Pirelli tyres to finish 0.072 seconds clear of Vettel with Lewis Hamilton 0.142s off the pace in third.

But Verstappen was told to return to the pits slowly after reporting that the car was "shifting by itself" while Red Bull team-mate Daniel Ricciardo clipped the wall, forcing him to back out of his final attempt at a low-fuel run.

Both Red Bulls returned to the track in the final seconds of the session, suggesting that neither situation caused any lasting problems.

McLaren continued its strong pace at Marina Bay with Fernando Alonso and Stoffel Vandoorne fourth and fifth respectively.

As the sun set, Vettel was the first driver to post a representative time, the Ferrari driver going quickest with 1m43.237s, but he clipped the wall on the exit of the penultimate corner in the process.

The Red Bulls hung back and didn't head out for their timed laps until midway through the session with Verstappen going fastest and Ricciardo second, 0.268s adrift of his team-mate.

The session was red-flagged after Marcus Ericsson had a low-speed spin, sending his Sauber into the wall backwards just after he had driven under the grandstand towards the end of the lap.

Ericsson recovered to the pits with a damaged rear end, but the marshals needed just under 10 minutes to sweep away the debris from the accident.

There was a flurry of activity when the session was restarted, with Vettel setting the fastest first and second sectors to go quickest with a 1m41.901s, 0.348s quicker than Verstappen.

The Red Bulls headed out in a bid to respond, with Verstappen reclaiming top spot by just a fraction of a second.

Ricciardo, who topped both Friday practice sessions, had to back out of his effort when he clipped the wall, and he ended up sixth quickest.

Hamilton's lap to go third left the top three split by just 0.142s.

Nico Hulkenberg was best of the rest in seventh for Renault, with Valtteri Bottas failing to improve on his final run and ending up six tenths adrift of Mercedes team-mate Hamilton.

Kimi Raikkonen, who said "not a lot of things made sense" for Ferrari in Friday practice, continued to struggle as he posted the ninth best time, eight tenths behind team-mate Vettel.

Force India's Sergio Perez closed out the top 10, a tenth clear of team-mate Esteban Ocon.