Sampdoria set a club record four straight victories at the start of a Serie A season with a 4-1 success over lowly Siena yesterday that took them top of the table.
Sampdoria lead Juventus, who won 2-0 against Livorno on Saturday, on goals scored to be the unlikely pace-setters at this early stage of the season.
It wasn't such good news for their city rivals Genoa, though, who could also have gone top but they lost their 100 per cent record with a 3-1 defeat at Chievo.
Meanwhile, Inter coach Jose Mourinho, who on Saturday launched a broadside at his Italian critics, was sent off for arguing with the referee as the champions came back from a first-half deficit to beat Cagliari 2-1 in Sardinia.
Brazilian Jeda gave the hosts the lead from the spot on 16 minutes while Samuel Eto'o went closest for the visitors before the break with a curling free-kick that flew just past the post.
But Argentine forward Diego Milito scored two in the first 11 minutes of the second period to give Inter a third win in four games.
Sampdoria scored through Angelo Palombo, Daniele Mannini and a Marco Padalino brace with Siena's consolation coming from Michele Fini.
But as ever it was former Real Madrid forward Antonio Cassano at the centre of everything for Sampdoria as he also provided his fourth assist in as many games.
Palombo got things under way on 23 minutes, shooting home low past Gianluca Curci in the Siena goal.
Cassano then set Mannini free on 31 minutes with a slide rule pass that his team-mate dinked cleverly over Curci.
Padalino added the third early in the second period and although Fini pulled a goal back, Padalino was on hand five minutes from time to knock home the rebound after striker Giampaolo Pazzini's shot had been blocked by Curci.
Neighbours Genoa lost their chance to return to the top in a disappointing performance.
They were 2-0 down inside seven minutes after Michele Marconi slotted home a penalty awarded for a foul by Giuseppe Biava on Erjon Bogdani, who then converted a cross from Luciano at the back post.
Sergio Floccari converted a second half spot-kick to give Genoa hope but Sergio Pellissier finished off the visitors 13 minutes from time.
Floccari had another chance to score from the spot deep into injury time but Stefano Sorrentino saved that effort.
Clarence Seedorf scored the only goal of the game as Milan laboured to a 1-0 home win over Bologna.
Catania earned their first point of the season with a 1-1 home draw against Lazio, leaving Atalanta bottom on zero points following another dreadful outing, a 4-1 thumping at newly-promoted Bari.
In last night's match, Francesco Totti hit a brace as Roma beat Fiorentina 3-1 at the Stadio Olimpico. The Roma captain opened the scoring with a 27th-minute penalty, given for a handsball by Alessandro Gamberini, and doubled the lead six minutes later with a close-range volley.
A thumping header from Daniele De Rossi four minutes from half-time all but secured Roma's second successive win under new coach Claudio Ranieri.
Alberto Gilardino's goal six minutes from time was a mere consolation for Fiorentina who slipped to their first defeat of the season.
Next fixtures
Wednesday: 20.45 Atalanta vs Catania; Bari vs Cagliari; Bologna vs Livorno; Fiorentina vs Sampdoria; Inter vs Napoli; Lazio vs Parma; Palermo vs Roma; Siena vs Chievo; Udinese vs Milan.
Thursday: 20.45 Genoa vs Juventus.