Mercedes star Nico Robserg bounced back from a crash in P1 to top the timesheets after the second practice session in Singapore.
Rosberg, who trails team-mate Lewis Hamilton by just two points in the Drivers' Championship, crashed in the first outing on Friday and ended up fifth fastest.
The German managed to hit back in the second session, though, and clocked a quickest time of 1:44.152 to take a slight mental advantage going into Saturday at the Marina Bay Street Circuit.
Hamilton, who is aiming for a fourth world title, was down in seventh at the end of the day but the majority of the time was focused on testing out the halo device.
The Briton will be hoping for an improvement in qualifying as he looks for a first victory in three attempts, having seen his lead slip after taking third and second in Belgium and Italy respectively.
Finland's Kimi Raikkonen enjoyed a good run in P2, finishing second, whilst Max Vertsappen, quickest in P1 for Red Bull, slipped down one position to third.
Daniel Ricciardo was following closely behind in fourth for the four-time Constructors' Champions while Sebastian Vettel ended up fifth for the Maranello-based outfit.
Toro Rosso's Carlos Sainz Jr was ninth, Fernando Alonso took ninth for McLaren while Daniil Kvyat, whose future past this season remains in doubt, made up the top 10.