Hamilton slumps to ninth in P2
Alonso grabs fastest time in closing stages
Britain's Lewis Hamilton was just ninth fastest in the second practice session ahead of Sunday's title-deciding Brazilian Grand Prix.
Former two-time world champion Fernando Alonso knocked championship leader Hamilton's title rival Felipe Massa off top spot in the closing stages of the afternoon programme at Interlagos.
Brazilian Massa was out in front in the opening session in his Ferrari, edging Hamilton into second place in his McLaren by 0.190 seconds with a lap time of one minute 12.305secs.
Although marginally slower in the afternoon, Massa was all set to again take the honours when Renault's Alonso stole his thunder with a lap of 1:12.296secs.
Hamilton only has to finish in the top five to take the title, but struggled in stark contrast to a fortnight ago when he dominated in China en route to victory.
Conditions were hardly welcoming either as a grey, windy day was punctuated by the odd shower, upsetting any rhythm.
Heavy rain is forecast on Sunday, and as Massa has proven over the course of the season to date, he and his car have been unable to handle such conditions, and that could play into Hamilton's hands.
On Friday, Hamilton finished over half a seconds down on former team-mate Alonso, with Toyota's Jarno Trulli third and Kimi Raikkonen fourth in his Ferrari.
Toro Rosso's Sebastian Vettel, Nelson Piquet for Renault and Nico Rosberg in his Williams were also ahead of Hamilton in sixth, seventh and eighth places.
Williams' Kazuki Nakajima completed the top 10, followed by Scot David Coulthard, who concludes his 15-season F1 career here in Sao Paulo on Sunday.
Jenson Button, meanwhile, was down in 18th in his Honda, over a second off Alonso's pace.
1 F. Alonso, Renault 1:12.296, 43 laps
2 F. Massa, Ferrari 1:12.353, 41 laps
3 J. Trulli, Toyota 1:12.435, 44 laps
4 K. Räikkönen, Ferrari 1:12.600, 32 laps
5 M. Webber, Red Bull 1:12.650, 45 laps
6 S. Vettel, Scuderia Toro Rosso 1:12.687, 47 laps
7 N. Piquet jr., Renault 1:12.703, 44 laps
8 N. Rosberg, Williams 1:12.761, 42 laps
9 L. Hamilton, McLaren 1:12.827, 33 laps
10 K. Nakajima, Williams 1:12.886, 42 laps
11 D. Coulthard, Red Bull 1:12.896, 38 laps
12 R. Kubica, BMW 1:12.971, 48 laps
13 N. Heidfeld, BMW 1:13.038, 49 laps
14 T. Glock, Toyota 1:13.041, 39 laps
15 H. Kovalainen, McLaren 1:13.213, 37 laps
16 R. Barrichello, Honda 1:13.221, 39 laps
17 S. Bourdais, Scuderia Toro Rosso 1:13.273, 41 laps
18 J. Button, Honda 1:13.341, 49 laps
19 A. Sutil, Force India F1 1:13.428, 32 laps
20 G. Fisichella, Force India F1 1:13.691, 33 laps