Sebastian Vettel proved that Red Bull will be a contender for its 13th pole position of the season by topping the times during the final free practice session ahead of the Italian Grand Prix.
The world championship leader banged in a lap of 1m23.170s on the third lap of a run on options to knock team-mate Mark Webber off the top of the timesheets by 0.364s.
Felipe Massa and Lewis Hamilton showed that Ferrari and McLaren have some work to do if they are to challenge for pole after ending up 0.498s and 0.571s off Vettel following their qualifying simulations, although with Alonso down in eighth place, almost one second off, there is a suspicion that there is more to come from Ferrari.
Virgin driver Jerome d'Ambrosio, running Virgin's major upgrade package, which features a modified diffuser/floor for the first time, was first to head onto the track ahead of HRT driver Tonio Liuzzi.
Everyone except Sebastian Vettel and McLaren pairing Lewis Hamilton and Jenson Button hit the track during the first five minutes of the session, with all but Williams driver Pastor Maldonado, who ran for two laps, completing a single installation lap.
Vettel, Hamilton and Button then also completed installation laps during a quiet start to the session.
With the track temperature at 29 degrees, cooler than yesterday when problems with blistering became apparent, d'Ambrosio, running medium (prime) compound Pirellis, became the first to complete a flying lap, briefly topping the timesheets with a time of 1m32.578s - just under three seconds off his best mark of yesterday afternoon.
He was quickly bumped off the top slot by the two Lotuses of Heikki Kovalainen and Jarno Trulli despite improving his time by 2.5s on his second lap.
Mercedes driver Nico Rosberg was the first front-runner to post a time, albeit one slower than the Lotuses and he outbraked himself on his second flying lap, forcing the Mercedes to straightline the chicane - a mistake he would make again later in the session. But team-mate Michael Schumacher did go fastest for Mercedes after 16 minutes with a lap of 1m26.943s. This was despite a very wide moment at the exit of the Ascari chicane.
Schumacher then repeated Rosberg's trick with a mistake at the first chicane, spinning mid-corner after losing the rear at turn in, at much the same time as Rosberg topped the times with a lap of 1m24.956s.
By this time, everyone except the Ferraris - who remained in the pits after two installation runs - Vettel and Hamilton had started setting times.
Most teams concentrated on running prime tyre in the first part of the session. With fears that the option tyres will not last long in the race, exploiting the full potential of the medium compound over a stint could be the key to the race.
After 21 minutes, Button went fastest, two-tenths quicker than Rosberg, on the fifth and final lap of his run on prime tyres. He was deposed three minutes later by Mark Webber, who showed sustained pace on prime rubber during his long run.
Team-mate Sebastian Vettel, then also on the seventh lap of a run, beat his time by 0.468s to go fastest after 28 minutes.
Outside of the top teams, Williams showed well in the early stages, with Pastor Madlonado sixth, 1.656ssecs off the pace, and Rubens Barrichello eighth, just under three-tenths of a second further back, after everyone except the Ferraris had completed their first runs on prime rubber.
At the halfway mark of the session, Alonso became the first Ferrari driver to set a time. Also running on prime rubber, he went 11th fastest on his first flying lap, two seconds off Vettel, improving by a quarter-of-a-second on his second lap to climb to seventh, just ahead of Massa. He improved to sixth overall, 1.247s off the pace, by the end of his run, almost two-tenths off Massa.
Toro Rosso driver Jaime Alguersuari was the first to attempt a run on the soft-compound option rubber. He didn't improve on his first lap, but found half-a-second on his first lap to climb to eighth, 1.8s off Vettel's time.
With 23 minutes remaining, Rosberg used option tyres to set the fastest time after two warm-up laps, blitzing the first and third sectors to knock Vettel off the top spot by 0.125s with a lap of 1m23.875s. Sauber driver Sergio Perez was the next to improve, using options to go ninth fastest, 1.630s off the pace.
Others opted to continue on prime tyres, with Renault driver Bruno Senna improving his time despite taking a bite of the gravel at the exit of Lesmo 2. Despite this, he remained down in 17th place as Renault concentrated on higher fuel work but did further improve to 15th overall with 15 minutes left.
By this time, Schumacher was on his option tyre run, setting a 1m24.114s after a couple of cool-off laps to go third fastest, 0.239s off Rosberg. But the option runners remained in the minority until the closing stages, setting up a dramatic series of qualifying simulations in the final 10 minutes.
Alonso was the first of the big three teams to launch his run on options. He went fourth fastest, 0.258s off Rosberg, with his first flying lap before backing off to cool off the tyres. Massa followed shortly after, climbing to sixth after benefitting from a two from Alonso on the run from Lesmo 2 to Ascari.
Button was next to improve at the front on options, climbing to second, just 21 thousandths off Rosberg, with five-and-a-half minutes remaining. But soon it was business as usual, with Webber setting fastest times in sectors two and three to go fastest, followed a few seconds later by Massa jumping to second, one-tenth behind him.
Vettel then slotted into third place, 0.189s off his team-mate, beating Webber's fastest time in the middle sector - but then straightlined the second chicane on his next lap.
With McLaren struggling to match the leaders, Hamilton climbed to third with one minute to go, two-tenths off Webber, but on the third lap of a run it was Vettel who took his traditional position at the top of the timesheets. At the same time, Button jumped to fifth ahead of Rosberg, but was still over six-tenths off.
Red Bull, Ferrari, McLaren and Mercedes locked out the top eight on the timesheets, and it was Force India that ended up their closest challengers, with Adrian Sutil and Paul di Resta putting in late fliers to take ninth and tenth ahead of the Renaults of Bruno Senna and Vitaly Petrov.
A number of drivers also had off-track moments during the session. Sebastien Buemi and Sergio Perez both straightlined the second chicane, while Virgin driver Timo Glock rattled over the speed bumps at Ascari. Rosberg had a third moment at the first chicane late on and was again forced to straightline it. Kovalainen also cut the second chicane during his final run.
Pos Driver Team Time Laps 1. Sebastian Vettel Red Bull-Renault 1m23.170s 18 2. Mark Webber Red Bull-Renault 1m23.534s + 0.364 19 3. Felipe Massa Ferrari 1m23.668s + 0.498 14 4. Lewis Hamilton McLaren-Mercedes 1m23.741s + 0.571 17 5. Jenson Button McLaren-Mercedes 1m23.787s + 0.617 16 6. Nico Rosberg Mercedes 1m23.875s + 0.705 22 7. Michael Schumacher Mercedes 1m24.114s + 0.944 20 8. Fernando Alonso Ferrari 1m24.133s + 0.963 14 9. Adrian Sutil Force India-Mercedes 1m24.543s + 1.373 21 10. Paul di Resta Force India-Mercedes 1m24.581s + 1.411 22 11. Bruno Senna Renault 1m24.853s + 1.683 20 12. Vitaly Petrov Renault 1m24.889s + 1.719 19 13. Sergio Perez Sauber-Ferrari 1m24.948s + 1.778 22 14. Kamui Kobayashi Sauber-Ferrari 1m25.261s + 2.091 21 15. Rubens Barrichello Williams-Cosworth 1m24.319s + 2.149 19 16. Jaime Alguersuari Toro Rosso-Ferrari 1m25.426s + 2.256 19 17. Sebastien Buemi Toro Rosso-Ferrari 1m25.439s + 2.269 22 18. Pastor Maldonado Williams-Cosworth 1m25.539s + 2.369 19 19. Jarno Trulli Lotus-Renault 1m27.328s + 4.158 19 20. Heikki Kovalainen Lotus-Renault 1m27.491s + 4.321 21 21. Jerome D'Ambrosio Virgin-Cosworth 1m28.186s + 5.016 23 22. Tonio Liuzzi HRT-Cosworth 1m28.441s + 5.271 22 23. Timo Glock Virgin-Cosworth 1m28.962s + 5.792 17 24. Daniel Ricciardo HRT-Cosworth 1m30.316s + 7.146 16
All Timing Unofficial