Nico Rosberg puts Mercedes back on top in FP2

After Mercedes spent the morning session solely using Pirelli's medium-compound tyres, the switch to softs in the afternoon at Barcelona's Catalunya circuit enabled Rosberg to set the leading time of 1m23.922s.

The lap came midway through the 90 minutes, dropping Ferrari's Kimi Raikkonen down to second, with the Finn finishing a quarter of a second adrift.

Shortly after the lap from Rosberg, Raikkonen was ordered to slow down and pit by his team due to a fuel system problem, one that was soon repaired as he later returned to the track.

Lewis Hamilton, running with an updated MGU-H this weekend following recent problems in China and Russia, finished 0.719s shy of team-mate Rosberg after his first outing on the soft rubber.

Sebastian Vettel finished just over a second adrift of Rosberg for fourth place, followed by Carlos Sainz in his Toro Rosso and Red Bull's Daniel Ricciardo.

Their respective team-mates in Daniil Kvyat and Max Verstappen, who swapped seats last week, finished 15th and eighth, with the Russian 1.5s adrift of Sainz.

Verstappen was at least closer to Ricciardo, with the 18-year-old less than two tenths of a second behind the Australian.

McLaren's Fernando Alonso was seventh quickest, that after running wide at one stage over a section of artificial grass that damaged his car's plank, forcing a replacement.

Team-mate Jenson Button also encountered problems as his car shut down early in the session on entry to the pits.

After the technical problem was repaired, Button's first lap back on track on soft tyres slotted him into 12th, just under two seconds behind Rosberg.

Renault encountered an eventful day, with reserve Esteban Ocon sustaining a right-rear puncture in FP1, leading to him completing just six laps and failing to set a time.

Come Jolyon Palmer's return to the car for FP2, the Briton suffered a spectacular puncture to the left-rear tyre along the main straight, leading to a red flag given the debris on the track.

After his car was recovered and returned to the pits, Palmer managed to get back on track, finishing 17th and almost 2.9s off the pace, and half a second down on team-mate Kevin Magnussen in 14th.

Haas duo Romain Grosjean and Esteban Gutierrez both complained over the radio about the handling of their car, the former swearing at one point in FP2 such was his frustration.

Grosjean eventually finished 13th, with Gutierrez down in 21st and only managing nine laps due to a technical problem that confined him to the garage for a lengthy period.