Briton Lewis Hamilton topped the times in Friday's delayed and curtailed opening free practice session ahead of Sunday's Singapore Grand Prix.
The 26-year-old Englishman threw his McLaren around the floodlit street circuit to produce a best lap time of one minute and 48.599 seconds, finishing half a second ahead of championship chasing Sebastian Vettel of Red Bull.
Vettel, who needs a victory and other drivers to fail to finish among the leaders if he is to take his second title on Sunday, revelled in his duel with Hamilton as the pair traded fastest laps in an ultimately absorbing session.
The pair met on their respective flights to Singapore and while Hamilton has conceded this year's championship to the German, he set up the weekend's competition with a different kind of sports challenge for his younger rival.
"I asked him if he played golf, because I would happily play golf with him. I don't know what else he does," said Hamilton.
"Maybe we should meet up on the autobahn in the same car. Then we'll see how it goes."
Their duel dominated a session twice red-flagged for interruptions after minor incidents as they finished clear of Australian Mark Webber of Red Bull.
Webber, one of the quickest men on street circuits, wound up ahead of two-times champion Spaniard Fernando Alonso of Ferrari, who is Vettel's closest championship rival, albeit running 112 points behind with six races remaining.
Briton Jenson Button was fifth in the second McLaren ahead of Brazilian Felipe Massa in the second Ferrari, German Adrian Sutil of Force India and his compatriot seven-times champion Michael Schumacher, 42, in the leading Mercedes.
Briton Paul di Resta was ninth for Force India and German Nico Rosberg 10th in the second Mercedes.
The start of the session was delayed by half an hour for track repairs to parts of loose curbing on the Marina Bay circuit deemed to be a danger for the F1 cars.
The delay meant the session was reduced to one hour instead of 90 minutes as the cars began to roar around the waterside track in South East Asia's smallest country under the glowing floodlights.
Once the action was underway, Rosberg, Schumacher and Massa topped the times early on, before Webber ran into German Timo Glock's Virgin and left front wing debris on the circuit, causing the first delay.
The second delay happened after Finn Heikki Kovalainen's Lotus burst into flames.
Later, Massa ran over loose plastic curbing that rose out of the road but by then it was clear the battle for supremacy was between Vettel and Hamilton as they traded the best times with the Briton ending the session on top.