Defending champion Inter Milan was held to a 1-1 draw by Udinese and European champion AC Milan rolled to a 3-0 win at Genoa as the title favorites opened the Italian league season on Sunday.
AS Roma, which is showing signs it could improve on its second-place finish last season, won 2-0 at Palermo with goals from Philippe Mexes and Alberto Aquilani. A week ago, Roma beat Inter in the Italian Supercup.
At San Siro, Inter defender Ivan Cordoba headed the ball into his own net following an Udinese corner in second-half injury time. Dejan Stankovic had put Inter ahead nine minutes in but Inter was reduced to 10 men when goalkeeper Julio Cesar was sent off for a handball outside the area in the 56th.
"In the first half we played well, we had a chance to close out the game and we didn't do it," Inter coach Roberto Mancini said.
Julio Ricardo Cruz had a clear chance to make it 2-0 in the first half but shot high.
Temperatures throughout Italy soared above 40?C as the afternoon games were played. Mancini said the match should have been played at night.
The draw added to Inter's rough start to the season. Besides the Supercup loss to Roma, Inter also lost defender Marco Materazzi to injury during Italy's friendly defeat to Hungary on Wednesday.
Kaka scored twice and Massimo Ambrosini added another as Milan cruised against Genoa, which returned to Serie A after a 12-season absence.
Milan coach Carlo Ancelotti predicted Kaka could be the league's leading scorer.
"I thought about it after the game. It wouldn't surprise me," Ancelotti said.
With 10 goals, Kaka led the Champions League last season.
Ambrosini headed in a free kick by Andrea Pirlo in the 21st and Kaka angled in a shot after Massimo Oddo ran up the right flank in the 44th. Kaka also converted a penalty in first-half added time after Alberto Gilardino was tripped by Genoa goalkeeper Rubens Rubinho.
"There's always the worry that you don't find your form right away. But we did well from the start," Ancelotti said. "Everything wasn't perfect but the squad had the right approach."
Filippo Inzaghi was rested for Friday's European super cup against Sevilla.
Milan fans were barred from the match for fears of a violent vendetta. Genoa fan Vincenzo Spagnolo was stabbed to death during a brawl with Milan supporters outside Luigi Ferraris stadium in 1995 and the two clubs had not met since.
No violence was reported.
In Palermo, Mexes redirected a cross from Rodrigo Taddei to put Roma ahead three minutes in and Aquilani scored from 25m in the 27th as Italy coach Roberto Donadoni looked on from the stands.