Lewis Hamilton completed a clean sweep of the opening two practice sessions ahead of Sunday's crucial Brazilian Grand Prix, topping the afternoon session ahead of both title contenders.
Although his first session time was set on the latest development tyres from Pirelli, the McLaren driver still lapped slightly faster in the afternoon, this time bettering points leader Sebastian Vettel by a couple of tenths, while the second Red Bull of Mark Webber rounded out an identical top three to the morning. Vettel, meanwhile, was a further two-tenths clear of the only man who can deny him a third successive championship crown, although Fernando Alonso appeared to have the better pace when both swapped from the medium 'option' tyre to the harder 'prime'.
Indeed, the Red Bull did not appear as comfortable on the harder rubber during race simulations as either of its likely frontrunning rivals, but the situation could be further clouded by a weather forecast that suggests that qualifying could be affected by showers and raceday by persistent rain that could mean that the title showdown takes place on a wet track.
Alonso was only fifth fastest in the afternoon session, trailing the other Ferrari of home favourite Felipe Massa, while Mercedes bounced back into the top ten, with both Michael Schumacher and Nico Rosberg lapping faster than Jenson Button, amid rumours that the Three Pointed Star had abandoned its 'double DRS' system as it tries ideas for 2013, when the technology will be outlawed.
Button was eighth fastest after lunch, 0.8secs slower than his team-mate as the two McLarens went in different directions with their rear wing settings, but had enough in hand to keep Lotus Romain Grosjean at bay. Force India filled tenth and eleventh, with Paul di Resta again ahead of Nico Hulkenberg, while Kimi Raikkonen complained of overheating tyres as he headed for twelfth spot.
Bruno Senna managed 13th place after his usual late entrance to the fray, having again sat out FP1 in favour of Valtteri Bottas, but still ended the afternoon session ahead of regular team-mate Pastor Maldonado. Interestingly, however, the Brazilian trailed Bottas on the combined times by just one-hundredth of a second. The Saubers of Sergio Perez and Kamui Kobayashi, as well as the Toro Rosso of Daniel Ricciardo, found themselves between the two Williams drivers, although Kobayashi was lucky not to incur more damage after launching his car off the kerbs at the bottom of the Senna S.
The second STR of Jean-Eric Vergne brought up the rear of the midfield after recording identical times in both 90-minute sessions, and was only a tenth of a second clear of Caterham's Vitaly Petrov. The Russian had the advantage of running on both sessions, and wound up half a second clear of team-mate Heikki Kovalainen, while Pedro de la Rosa gave the beleaguered HRT a brief fillip by appearing in 21st spot, ahead of both Marussias and team-mate Narain Karthikeyan. The Spaniard dropped back into the bottom two when the combined times were analysed, while Marussia's Charles Pic was hampered in his efforts to improve by a suspected alternator failure that limited his afternoon running.