Sebastian Vettel put in a late charge on the soft Pirelli tyres to claim the fastest lap in final practice ahead of the Spanish Grand Prix.
The reigning world champion will take the advantage into Saturday afternoon's qualifying session, but Sauber are also looking good.
Red Bull star Vettel topped the timesheets with a lap of one minute 23.168 seconds around the 4.655km Circuit de Catalunya - just before the session ended.
He was 0.168s quicker than Williams driver Pastor Maldonado in second, with Sauber's Kamui Kobayashi third ahead of Red Bull's Mark Webber.
Another Sauber, that of Sergio Perez, was fifth ahead of Ferrari's Fernando Alonso, with Jean-Eric Vergne (Toro Rosso), Jenson Button (McLaren), Kimi Raikkonen (Lotus) and Nico Rosberg (Mercedes) completing the top 10.
Lewis Hamilton posted the fastest time in the first two sectors at one stage and was poised to top the timesheet with three minutes remaining.
But in the final chicane Hamilton found himself blocked by Kimi Raikkonen in his Lotus, resulting in the 27-year-old finishing down in 16th, 1.610secs off the pace.
Felipe Massa completed a remarkable sequence as he wound up 11th after finishing 12th and 11th in FP1 and FP2 respectively, with his times 1.003secs, 1.019secs and 1.011secs off the leader.
Despite sporting an upgrade package they hoped would propel them closer to the top 10, the Force India duo of Nico Hulkenberg and Paul di Resta appear to be struggling, the latter nearly 1.5secs down in 15th.
Lotus' Romain Grosjean propped up the standings, albeit without setting a time due to a fuel pressure problem that restricted him to nothing more than two installation laps.
Times
01 Sebastian Vettel Red Bull 1:23.168 13 laps
02 Pastor Maldonado Williams 1:23.336 0.168 19 laps
03 Kamui Kobayashi Sauber 1:23.350 0.182 19 laps
04 Mark Webber Red Bull 1:23.578 0.410 16 laps
05 Sergio Perez Sauber 1:23.742 0.574 22 laps
06 Fernando Alonso Ferrari 1:23.807 0.639 15 laps
07 Jean-Eric Vergne Toro Rosso 1:23.833 0.65 14 laps
08 Jenson Button McLaren 1:23.909 0.741 13 laps
09 Kimi Raikkonen Lotus 1:23.936 0.768 16 laps
10 Nico Rosberg Mercedes 1:24.070 0.902 24 laps
11 Felipe Massa Ferrari 1:24.179 1.011 16 laps
12 Nico Hulkenberg Force India 1:24.323 1.155 17 laps
13 Daniel Ricciardo Toro Rosso 1:24.331 1.163 15 laps
14 Bruno Senna Williams 1:24.409 1.241 18 laps
15 Paul di Resta Force India 1:24.599 1.431 15 laps
16 Lewis Hamilton McLaren 1:24.778 1.610 15 laps
17 Michael Schumacher Mercedes 1:24.825 1.657 17 laps
18 Vitaly Petrov Caterham 1:25.911 2.743 20 laps
19 Heikki Kovalainen Caterham 1:26.587 3.419 20 laps
20 Charles Pic Marussia 1:27.469 4.301 18 laps
21 Timo Glock Marussia 1:27.689 4.521 17 laps
22 Narain Karthikeyan HRT 1:28.207 5.039 24 laps
23 Pedro de la Rosa HRT 1:28.373 5.205 13 laps
Romain Grosjean Lotus no time 2 laps
