Nico Rosberg stole the fastest time in final free practice for the Malaysian Grand Prix to thrust Mercedes firmly into the reckoning for pole position at Sepang.
The German, who began the hour-long session looking concerned as his mechanics struggled to work on a newly-fitted Mercedes engine, produced the first lap of the weekend under 1min 37secs to knock fellow countryman Sebastian Vettel off top spot in the dying moments, confirming the Three-Pointed Star as a genuine qualifying contender. Times tumbled in the second half of the session, once the light shower that interspersed the GP2 race and F1 practice had passed over and allowed the track to dry. The benchmark appeared stuck in the 1min 37s, however, until Rosberg struck with a minute or two remaining before the chequered flag.
Mercedes' candidature was emphasised by the four-tenths cushion between him and the Red Bulls, although neither McLaren threatened P1 and it remains to be seen whether there is more to come from Friday pacesetter Lewis Hamilton and Australian GP winner Jenson Button. Vettel claimed second spot narrowly ahead of RBR team-mate Mark Webber, after both had taken turns in top spot on a more encouraging day for the Milton Keynes equipe
, while Lotus duo Kimi Raikkonen and Romain Grosjean shrugged off any distraction caused by the overnight first in the team's weekend headquarters to slot into fourth and fifth respectively.
That all meant that the leading McLaren was only sixth, with Button's best over half a second off Rosberg's pace. Team-mate Hamilton, meanwhile, completed only eight laps in the hour, but hauled himself off the bottom of the times - the result of a major tankslapper going through turns 13-14 - to bounce back into ninth spot. Williams' Pastor Maldonado, who held top spot for some time with a 1min 37.455secs best, and the second Mercedes of Michael Schumacher filled the gap between the two McLarens, while Kamui Kobayashi completed the top ten for Sauber.
Eleventh place went to Bruno Senna, who carried out the majority of the early running, but still waited 20 minutes before setting a time, as he attempted to make up for the session he handed to Williams reserve Valtteri Bottas on Friday, while Sergio Perez also sneaked ahead of the leading Ferrari, driven by Fernando Alonso, in 13th position. With team principal Stefano Domenicali admitting that there was no miracle cure for the Scuderia's woes, Alonso was 1.3secs off the pace, and team-mate Felipe Massa another second adrift in 18th overall.
Force India and Toro Rosso filled the places between the two scarlet cars, the Italian outfit unable to replicate its Friday performance despite Daniel Ricciardo appearing briefly in third position, while Vitaly Petrov got the better of Caterham team-mate Heikki Kovalainen by a matter of tenths to round out the top twenty. Charles Pic got one over on Marussia team-mate Timo Glock for the first time, albeit by a tenth, while there was better news for HRT, who had Pedro de la Rosa and Narain Karthikeyan lapping within 107 per cent of Rosberg's target.