Ferrari and Red Bull appear poised to claim a first pole position of the season at the Singapore Grand Prix after both teams easily outpaced Mercedes in the final free practice session.
Four-time world champion Sebastian Vettel was in supreme form around the Marina Bay Street Circuit, lapping almost half a second faster than his Ferrari teammate Kimi Raikkonen to top the timesheets in 1 minute, 45.682.
The Red Bulls of Daniil Kvyat and Daniel Ricciardo were close behind as championship leader Lewis Hamilton and his Mercedes team mate Nico Rosberg toiled more than a second off the pace as the sun set over Singapore.
The lack of pace will worry the German outfit, whose superior engine lacks a clear advantage around the tight, 23-turn circuit with the hot and humid conditions set to scupper the team's hopes of securing a 13th pole in as many races.
The championship leaders have two hours to try and eat into the time gap ahead of qualifying but on the evidence of Friday's second practice and the hour-long session on Saturday, Ferrari and Red Bull could well lock out the front two rows of the grid.
Starting the final session in twilight on a muggy yet clear evening, the main contenders waited 15 minutes before venturing out on to the circuit.
