Andrew Dampf
Inter, the three-time defending champion, won 3-1 at Torino with an own-goal created by Amantino Mancini and scores from Maicon and Zlatan Ibrahimovic.
Amauri scored his second goal in two games as Juventus beat Cagliari 1-0 with goalkeeper Gianluigi Buffon exiting at halftime with an apparent thigh problem.
Inter and Juventus lead with seven points each. Lazio, Palermo, Catania and Atalanta are next with six points each.
Lazio were bringing a perfect record into the San Siro later against AC Milan, who lost their opening two matches.
Palermo got goals from Uruguay's Edison Cavani and Cesare Bovo in a 2-1 win over Genoa.
Napoli moved to five points after holding on a for a scoreless draw at Udinese with 10 men.
Fiorentina have four points after beating Bologna 1-0 with a goal from Alberto Gilardino, the Italy forward's fifth in all competitions this season.
Perfect start
On Saturday, AS Roma snapped out of their early season funk with a 3-0 win over Reggina and Catania beat Atalanta 1-0 to end the Bergamo club's perfect start.
Also Sunday, Lecce-Siena and Sampdoria-Chievo Verona each ended 1-1.
In midweek action, Inter beat Panathinaikos 2-0 and Juventus posted a 1-0 win over Zenit St. Petersburg in the Champions League.
At Turin's Stadio Olimpico, Inter coach Jose Mourinho surrounded Ibrahimovic with Mancini and Adriano. Mancini took a pass from Adriano and sent a cross toward the box that was deflected in by Torino defender Marco Pisano in the 24th.
Two minutes later, Ibrahimovic began the play that ended with Maicon scoring with a shot from the edge of the area that banged in off the underside of the crossbar.
Ibrahimovic scored his second goal of the season in the 51st by slipping behind the defence on a counterattack.
Elvis Abbruscato pulled one back for Torino in the 76th, then hit the crossbar in the 86th.
In Sardinia, with David Trezeguet out facing knee surgery and captain Alessandro Del Piero banged up after scoring the winner against Zenit, Vincenzo Iaquinta set up Amauri's goal with a slight touch inside the area.
Amauri, who also scored in Juve's 1-0 win over Udinese last weekend, had a goal disallowed two minutes in for a foul by Iaquinta.
Buffon's replacement, Alex Manninger, preserved the win with a save from Alessandro Matri in the 90th.