Button tops first practice

The McLaren driver set his benchmark time of a minute 23.693 seconds after 52 minutes of the 90-minute session, having taken over P1 from Red Bull's Vettel on his previous flying lap.

It took the teams and drivers a long time to settle in at the notoriously super-fast Italian track.

Michael Schumacher was the only man to record a lap-time in the opening 23 minutes, when Jaime Alguersuari joined him on the quiet circuit.

The German came in at the end of his second stint - having completed nine competitive times with a best of 1:26.038 - with an hour remaining.

As he did do, Hamilton instantly smashed his mark with his first flying lap in the McLaren of 1:25.816, and continued to improve from there.

Vettel showed the Red Bull's teeth by going 0.001 behind the Briton's best then taking over P1, a position he held for six minutes.

Rubens Barrichello's session ended at the halfway point after he lost drive at the Lesmo section while Bruno Senna, not long out on track in his HRT, was another retiree later.

The latter stages of the practice were spent by the major teams trying out hard tyres over long stints and as such there was little change in the top places.

Vettel tried to challenge reigning champion Button - whose McLaren, like that of Hamilton, was running with extensive rear downforce - to no avail, finishing 0.097s off the pace.

Hamilton was over a quarter of a second behind his team-mate with Renault's Robert Kubica fourth ahead of Nico Rosberg, Mark Webber in the second Red Bull, Force India's Vitantonio Liuzzi, the Ferraris of Fernando Alonso and Felipe Massa and Schumacher.

After the chequered flag Rosberg left the track and clipped a polystyrene marker board with the front wing of his Mercedes, but any damage will be small.

Force India's Scottish test driver Paul Di Resta enjoyed a decent run in 12th behind Nico Hulkenberg.