Nico Rosberg's Mercedes narrowly headed Red Bull's Max Verstappen in final practice at the Singapore Grand Prix as Lewis Hamilton struggled.
Friday was tough for Hamilton, who was unhappy with his car and missed half a session with a technical problem.
His issues continued before qualifying on Saturday - he locked his brakes and missed Turn Seven on his fastest lap and ended up eighth fastest.
Rosberg was just 0.059 seconds ahead of Verstappen.
Ferrari's Kimi Raikkonen was third fastest, but 0.508secs off the pace and just 0.043secs ahead of the second Red Bull of Daniel Ricciardo.
Sebastian Vettel complained of a lack of rear-end grip as he ended up fifth fastest and 0.752secs behind Rosberg.
The four-time champion was not the only big name to struggle. Jenson Button was in all sorts of trouble in his McLaren, down in 16th place - four places but a massive 1.1secs slower than team-mate Fernando Alonso.
Verstappen's pace, set on a beautifully fluid lap by the Dutchman around the challenging Marina Bay Circuit, suggests Red Bull could - as expected - be a major threat to Mercedes' pace when qualifying starts at 14:00 BST.
Red Bull team principal Christian Horner said: "We know they always have a bit up their sleeve when they turn things up for qually, but it was a pretty decent session. Daniel lost a bit of time behind Ocon so his time wasn't representative."
Asked if Red Bull could take pole position, Horner said: "I doubt it. Lewis locked his front and flat-spotted so we didn't see his true pace and Rosberg looks like he has 0.1-0.2secs in there but we will see what happens."