Red Bull driver Daniil Kvyat sprung a surprise as he topped the second practice session at the Singapore Grand Prix.
Kvyat set a time of 1:46.142 as drivers conducted qualifying runs on Super Soft tyres, finishing 0.039s clear of Ferrari rival Kimi Raikkonen.
Daniel Ricciardo was a tenth of a second further back in third position despite being compromised by Sebastian Vettel on his hot lap.
Mercedes could manage only fourth and seventh, with Lewis Hamilton over three tenths down on Kvyat and Nico Rosberg a further tenths behind the Briton.
They were split by Vettel and Force India driver Sergio Perez, who set his fastest time slightly later than his rivals.
Fernando Alonso demonstrated McLaren’s pace by placing eighth, just over eight-tenths of a second down on Kvyat.
Nico Hulkenberg was ninth for Force India, while Max Verstappen rounded out the top 10 in the Toro Rosso.
Williams endured another lowly Friday as Felipe Massa was 11th, with Valtteri Bottas down in 17th place in the FW37, which has struggled on similar circuits in 2015.
Felipe Nasr led team-mate Marcus Ericsson in 12th position as the pair sampled the upgraded Sauber, which features a heavily revised nose.
Jenson Button was unable to match Alonso’s efforts and placed 14th, with Carlos Sainz Jr. suffering a tyre failure after clipping the wall at Turn 5 en-route to 15th.
Romain Grosjean and Pastor Maldonado collected 16th and 18th, the Venezuelan surviving a moment exiting Turn 10.
Alexander Rossi was able to join the action with only 20 minutes remaining following his crash during the first session and placed 19th.
Will Stevens’ session came to an early end when he spun at the revised Turn 12 and made minor contact with the barriers, bringing out the red flags.