Lewis Hamilton could again prove to be a fly in the ointment ahead of this weekend's title showdown in the Brazilian Grand Prix.
Although no longer involved in the championship battle, Hamilton has designs on finishing his 14-year association with McLaren with back-to-back victories after completing yesterday's final practice with the team by setting the fastest times in both sessions.
In Sunday's United States Grand Prix, Hamilton proved a thorn in the side of Sebastian Vettel by denying the 25-year-old the win that would have seen him take a 20-point lead over title rival Fernando Alonso.
Instead, Vettel's cushion is only 13 points going into the eagerly-anticipated race at Interlagos -- with one of the two due to become a three-time Formula One world champion.
Hamilton, who will join Mercedes next season on a three-year contract, topped the timesheet with a lap around the undulating 4.309km track of one minute 14.026secs.
Vettel, who had finished second to Hamilton in FP1 by just 0.009secs, was a little further adrift in FP2, falling 0.274secs behind in his Red Bull.
Team-mate Mark Webber was half a second off the pace, and had the Ferraris of Felipe Massa and Alonso in close attendance as they finished 0.527secs and 0.556secs adrift respectively.
Heavy rain continues to be forecast for tomorrow, with the only real question being when it will hit Sao Paulo -- before, during or after the race.
Alonso certainly requires any variable to assist his cause if he is to nick the championship from Vettel.
Behind the leading quintet, on his 308th and final grand prix before retiring for a second time, seven-time champion Michael Schumacher at least suggested he could bow out on a respectable note. The 43-year-old was sixth quickest in his Mercedes, just in front of team-mate Nico Rosberg, just over six-tenths of a second down.
They were followed by Jenson Button in his McLaren and Lotus' Romain Grosjean. Kimi Raikkonen was down in 12th in his Lotus and struggling as he complained of lack of grip from his tyres.