While top team Red Bull battled, returning world champion Kimi Raikkonen emerged the surprise pace-setter in final testing for the 2012 Formula One season.

The moody Finn was smiling yesterday after his Lotus prepared for next week's season-opening Australian Grand Prix with the quickest lap at Catalunya.

The 2007 drivers champion, who is back in F1 after a three-year absence, stopped the clock at 1 minute 22.030 seconds - the best time of both Barcelona test sessions.

Raikkonen completed 121 laps in the Lotus, formerly Renault, which capped an impressive week for the team.

Lotus headed the timesheets with the fastest lap on three of the four test days, with Raikkonen's teammate, Frenchman Romain Grosjean, topping the grid on Thursday and Friday.

Torro Rosso's new Australian driver, Daniel Ricciardo, stamped his mark on the week when he recorded an overall fourth fastest time of 1:22:155.

While the teams were running unknown fuel levels and some were trialing parts and set-ups, rather than chasing eye-catching laps aimed at luring sponsors, Ricciardo did finish ahead of compatriot Mark Webber.

Webber put in a solid 172 laps in his Red Bull for a 14th fastest time of 1:22.662. His teammate, reigning world champion Sebastian Vettel, was last in the field of 11 drivers on the final day due to a series of problems and only completed a session-low 23 laps.

''This morning I had an issue. I went off track and broke the front wing and had to come in,'' Vettel said. ''It took quite a while to get back out and then, just before lunch, we had a problem with the gearbox so it upset the whole day.

''After that, there wasn't much we could constructively do.''

Ferrari's Fernando Alonso was second fastest, 0.220 seconds off Raikkonen's pace. AAP