Sebastian Vettel set the pace in the final free practice session for the European Grand Prix in Valencia as things began to get serious on the dusty track.
The Red Bull driver was 0.42sec faster than Fernando Alonso, with Felipe Massa third and Mark Webber in the second Red Bull fourth.
Jenson Button was the quickest McLaren in fifth ahead of Nico Rosberg, Lewis Hamilton and Michael Schumacher. The two Renaults of Vitaly Petrov and Nick Heidfeld completed the top 10.
It was all about Red Bull and Ferrari again in P3 as the balance of power swung between the two teams at different phases of the session.
Massa was the first serious player to hit the top of the times with a 1m40.891s just before the halfway point, but that lasted mere seconds before Alonso re-established the mark with a 1m39.743s. It was his second attempt having backed out in sector three on his previous run.
Just as it was beginning to look a bit like Friday all over again, the Red Bulls then emerged from the pits as the session moved into the last half hour.
Equipped at this stage with the medium prime Pirelli tires, Vettel moved the goalposts with a 1m38.999s. The champion then re-emphasized Red Bull's prime tire position with a 1m38.694s, comfortably faster than the Ferraris.
As the German continued imperiously on, his teammate Webber moved to second in the sister Red Bull.
Not long after all this, teams began switching to the option Pirelli and Nico Rosberg proved the one-lap pace of the soft tire by going quickest with a 1m38.580s, while Mercedes teammate Michael Schumacher shot to third.
This signaled the switchover as all the frontrunners flowed out on the yellow-painted boots. First Massa, and then Alonso returned to the top of the times again, the Spaniard's lap of 1m37.678s actually standing until the last three minutes of the session.
That was when Vettel embarked on a red hot flying lap on the softs to go emphatically quickest with a 1m37.258s lap. That in spite of distractions from Narain Karthikeyan's HRT and one of the Lotus cars pitting in front of him.
The German went for it again as the session came to a close, but was slowed by yellow flags at the final corner after Kamui Kobayashi had a major moment when he lost the rear end and shot off down the infinite escape zone, damaging his Sauber's nose in the process.
Vettel's time then, four tenths faster than Alonso's best, would set the tone for qualifying. While McLaren was a second away at best with Button's fifth-fastest lap.
Pos Driver Team/Car Time Gap Laps
1. Sebastian Vettel Red Bull-Renault 1m37.258s 15
2. Fernando Alonso Ferrari 1m37.678s + 0.420s 16
3. Felipe Massa Ferrari 1m37.840s + 0.582s 17
4. Mark Webber Red Bull-Renault 1m38.068s + 0.810s 13
5. Jenson Button McLaren-Mercedes 1m38.326s + 1.068s 13
6. Nico Rosberg Mercedes 1m38.580s + 1.322s 15
7. Lewis Hamilton McLaren-Mercedes 1m38.741s + 1.483s 13
8. Michael Schumacher Mercedes 1m38.799s + 1.541s 14
9. Vitaly Petrov Renault 1m38.822s + 1.564s 17
10. Nick Heidfeld Renault 1m39.113s + 1.855s 15
11. Adrian Sutil Force India-Mercedes 1m39.411s + 2.153s 19
12. Sergio Perez Sauber-Ferrari 1m39.778s + 2.520s 18
13. Paul di Resta Force India-Mercedes 1m39.823s + 2.565s 18
14. Kamui Kobayashi Sauber-Ferrari 1m39.848s + 2.590s 18
15. Sebastien Buemi Toro Rosso-Ferrari 1m39.888s + 2.630s 17
16. Rubens Barrichello Williams-Cosworth 1m39.987s + 2.729s 18
17. Pastor Maldonado Williams-Cosworth 1m40.004s + 2.746s 16
18. Jaime Alguersuari Toro Rosso-Ferrari 1m40.239s + 2.981s 20
19. Heikki Kovalainen Lotus-Renault 1m41.267s + 4.009s 15
20. Jarno Trulli Lotus-Renault 1m41.690s + 4.432s 18
21. Timo Glock Virgin-Cosworth 1m42.557s + 5.299s 18
22. Tonio Liuzzi HRT-Cosworth 1m43.243s + 5.985s 17
23. Jerome D'Ambrosio Virgin-Cosworth 1m43.309s + 6.051s 18
24. Narain Karthikeyan HRT-Cosworth 1m44.630s + 7.372s 19
All timing unofficial