Lewis Hamilton appeared to be stamping his authority on the Malaysian GP with a stunning lap time in final practice.
The world champion was 0.619 seconds quicker than Mercedes team-mate Nico Rosberg as the teams prepared for qualifying, which starts at 10:00 BST.
The margin was even bigger after each had done one lap on soft tyres - 0.859secs - but Rosberg improved on a second lap.
Red Bull's Max Verstappen split the Mercedes, 0.445secs behind Hamilton.
The Dutchman's team-mate Daniel Ricciardo was down in sixth, but did not do a qualifying-simulation run late in the session.
Ricciardo was behind Ferrari's Kimi Raikkonen and Sebastian Vettel, the Finn 0.02secs quicker than the four-time world champion.
Vettel had a spin midway through the session at the tricky final corner, which has been reprofiled so it is now off-camber.
Force India's Nico Hulkenberg was seventh ahead of Williams' Valtteri Bottas and Toro Rosso's Carlos Sainz.
Jenson Button could manage only 12th fastest for McLaren, while team-mate Fernando Alonso concentrated on race preparation work because he has a 45-place grid penalty for taking too many engine parts and was slowest of all.