Rome  - Juventus new arrival Diego proved his worth Sunday scoring a brace in a 3-1 win the Turin side snatched in a classic Serie A match.

Roma suffered a second defeat from as many games before a 70,000-strong crowd at Rome's Stadio Olimpico, while Juve now top the standings on six points.

Inter Milan trail on four points, but Saturday made clear their intention to retain the Serie A title through a 4-0 drubbing of AC Milan in a city derby that the Devils played for the most part with 10 men.

After a fairly slow start, Juve's Portuguese midfielder Tiago on 22 minutes threatened with a header off a Diego free kick to force a first difficult save from Julio Bertagnolli.

The Brazil goalkeeper stood no chance three minutes later as his compatriot Diego dispossessed Marco Cassetti in midfield and raced toward Roma's goal to score by the far post despite John Riise's desperate opposition.

Roma's equalizer 10 minutes later owed much to the ingenuity of Juve's defence on a free kick that Daniele De Rossi fired past a dithering Gianluigi Buffon.

The international goalkeeper made amends before the half-time whistle, prodigiously blocking a nasty shot from the spurting Francesco Totti.

Another mouthwatering chance had gone begging for Juve on 43 minutes as Brazilian Amauri curled a low drive that came off the far post to the left of Bertagnolli.

After the break, the Juve striker saw his close-range effort saved before Iaquinta on 57 minutes had a counter-attack run blocked by former Inter Argentine Nicolas Burdisso.

Two more chances went begging for Iaquinta and Amauri before Diego scored his second goal on 68 minutes, this time getting the best of Philippe Mexes off a feed from Iaquinta.

A wide drive from Jeremy Menez and a Totti shot that came off the post from the distance were Roma's main threats for Buffon, while Diego tried another long-range effort with seven minutes to go and his countryman Felipe Melo notched a third goal in injury time.

Seven other games completed the second round of play late Sunday, leaving Lazio, Genoa and Sampdoria level with Juve on six points.

Italian Supercup winners Lazio thanked former Argentine Inter striker Julio Cruz for his brace in a 2-1 win clinched away to Chievo despite the second-half dismissal of Brazil defender Sanchez Cribari.

Samp beat Udinese 3-1, and Genoa won 1-0 at Atalanta, while Fiorentina also prevailed 1-0 at home to Palermo.

Napoli won 3-1 over newcomers Livorno with striker Fabio Quagliarella twice on target, Siena also beat hosts Cagliari 3-1 thanks to Emanuele Calaio's brace and promoted Parma beat Catania 2-1.

Earlier Saturday, promoted Bari drew 0-0 at home to Bologna a week after the far more prestigious draw they snatched away to Inter in the season opener. (dpa)