Sebastian Vettel closed out practice for the Singapore Grand Prix quickest as Ferrari rose to the front of the pecking order on Saturday evening.
Vettel posted a fastest lap time of 1:45.682 to finish half a second clear in top spot ahead of teammate Kimi Raikkonen, leaving Red Bull to settle for P3 and P4 with Daniil Kvyat and Daniel Ricciardo.
Ferrari and Red Bull led for the majority of the final practice session in Singapore as defending champions Mercedes once again struggled to match them for pace.
On the soft tire runs early on, Vettel set the pace, running half a second clear of Kvyat behind. Ricciardo was the first to make the switch to the super-softs for Red Bull, rising up into P1 with his first flying lap on the quicker compound.
However, Vettel quickly re-established his dominance by going faster still, creating a Ferrari one-two at the top of the timesheets alongside teammate Kimi Raikkonen. Kvyat slotted into third place with his qualifying simulation, edging out Ricciardo in the sister Red Bull.
The biggest surprise of the session came from Mercedes as Lewis Hamilton and Nico Rosberg once again failed to keep up with the Ferrari and Red Bull drivers. They eventually settled for fifth and sixth place respectively, prompting concern in the Mercedes garage that it may miss out on pole position for the first time in 2015 later today.
Fernando Alonso put in another solid display for McLaren to finish seventh, lapping just 0.04 seconds off the time of Rosberg in the Mercedes. Carlos Sainz Jr. followed his compatriot home in P8 for Toro Rosso, with teammate Max Verstappen and Sauber’s Marcus Ericsson rounding out the top ten.
American driver Alexander Rossi enjoyed a trouble-free final practice session for Manor, finishing 19th overall ahead of teammate Will Stevens.
At the front, a real fight looks to be on the cards in qualifying if Mercedes cannot hoist itself out of its struggles. The German marque has started on pole at every single race so far this season, but Ferrari could be poised to end that streak today.
Qualifying for the Singapore Grand Prix is live on CNBC and Live Extra from 9am ET on Saturday.