Lewis Hamilton topped the timesheets at Monza on Friday afternoon, edging Jenson Button in a closely-fought practice session.
With the track temperature up to a sweltering 40'C, Jerome D'Ambrosio, filling in for the banned Romain Grosjean, got proceedings underway with a 1:30.609. The Belgian was quickly down the order as the drivers did not waste any time getting down to business.
Kimi Raikkonen set the early pace with a 1:26.093 but was soon dropped as Belgian GP winner Jenson Button hit the front before he too lost out, this time to Nico Rosberg, while it was Fernando Alonso who was leading the way after the first 30 minutes with a 1:25.350.
Mercedes ran into a few problems when both Michael Schumacher and Rosberg suffered DRS problems with their rear wings. Merc revealed that Schumacher would run without the device for the rest of the session.
Despite swapping to the medium compound tyres just before the halfway stage, Alonso's first lap time was slower than his best on the harder Pirellis. This was repeated by others with Serio Perez and Rosberg also slower on their first attempts.
Alonso soon headed back into the pits have told his Ferrari team that something "broke" on the left front of his Ferrari, which was reported to be brake related. The Spaniard was still in front at the halfway point.
While the Spaniard was in the pits Button hit the front with a 1:25.328, the first driver to improve his time on the medium tyres. He was overhauled by his team-mate Lewis Hamilton, who was 0.038s quicker.
With 30 minutes remaining it was McLaren, McLaren, Ferrari, Ferrari, Mercedes, Lotus. The big omission is that mix: Red Bull. They were 11th and 13th with Mark Webber ahead of Sebastian Vettel.
More problems for Alonso as he returns to the pits, this time it was his gearbox. It seemed to be game over as he climbed out of his stricken Ferrari. Narain Karthikeya joined Alonso on the sidelines with HRT reporting a "small" technical problem with his car.
With drivers struggling to up the pace in the final few minutes, Practice Two ended with Hamilton quickest with his 1:25.290 ahead of Button and Alonso.
01 Lewis Hamilton McLaren 1:25.290 32 laps
02 Jenson Button McLaren 1:25.328 0.038 35 laps
03 Fernando Alonso Ferrari 1:25.348 0.058 17 laps
04 Felipe Massa Ferrari 1:25.430 0.140 42 laps
05 Nico Rosberg Mercedes 1:25.446 0.156 40 laps
06 Kimi Raikkonen Lotus 1:25.504 0.214 41 laps
07 Paul di Resta Force India 1:25.546 0.256 40 laps
08 Nico Hulkenberg Force India 1:25.547 0.257 36 laps
09 Sergio Perez Sauber 1:26.068 0.778 32 laps
10 Michael Schumacher Mercedes 1:26.094 0.804 38 laps
11 Mark Webber Red Bull 1:26.104 0.814 35 laps
12 Jerome d'Ambrosio Lotus 1:26.157 0.867 35 laps
13 Sebastian Vettel Red Bull 1:26.394 1.104 31 laps
14 Pastor Maldonado Williams 1:26.404 1.114 41 laps
15 Daniel Ricciardo Toro Rosso 1:26.724 1.434 32 laps
16 Kamui Kobayashi Sauber 1:26.730 1.440 17 laps
17 Bruno Senna Williams 1:26.783 1.493 39 laps
18 Heikki Kovalainen Caterham 1:26.841 1.551 39 laps
19 Jean-Eric Vergne Toro Rosso 1:26.864 1.574 36 laps
20 Vitaly Petrov Caterham 1:27.222 1.932 35 laps
21 Timo Glock Marussia 1:27.944 2.654 36 laps
22 Charles Pic Marussia 1:27.968 2.678 35 laps
23 Pedro de la Rosa HRT 1:28.575 3.285 34 laps
24 Narain Karthikeyan HRT 1:28.779 3.489 21