A hat-trick from Edinson Cavani gave Napoli a 3-1 comeback win over defending champions AC Milan on Sunday and top spot in Serie A.
Napoli have a perfect six points from two matches and lead the way on goal difference from Juventus, Udinese and Cagliari, while Milan, with just a point from two games, are fourth from bottom.
The champions took the lead in Naples when Alberto Aquilani rose to head in a precise cross from Antonio Cassano after 11 minutes.
But Uruguayan star Cavani pulled Napoli level two minutes later by cheekily nudging the ball between the legs of goalkeeper Christian Abbiati.
He then combined with international team-mate Walter Gargano to put Napoli in front in the 36th minute.
Cavani added the third in the 52nd minute when Ezequiel Lavezzi pounced on an error by Alessandro Nesta and crossed for the striker nicknamed 'Matador' to complete his hat-trick.
Juventus also maintained their perfect start to the season with a 1-0 win at Siena on Sunday, in a match that saw the Turin club's new coach Antonio Conte get one over on the team he left in the summer.
Conte cut his teeth as an assistant coach at the modest Tuscan club and returned last year to lead them to promotion back into the top flight.
However, his new-look Juve team -- fresh from thumping Parma last week -- spoiled Siena's first home game of the campaign by running out 1-0 winners at the Artemio Franchi stadium.
Alessandro Matri got the game's only goal nine minutes into the second half after Mirko Vucinic had done the spadework.
After two disappointing seasons in which Italian football's most successful club have finished in a lowly seventh place, excited supporters are now hoping to see their team end the Milan clubs' domination of the Scudetto.
However, Conte was eager to play down expectations afterwards.
"The title? It's far too early for such talk," he told Sky Italia.
Udinese made it two wins from two as they got the better of Fiorentina at Stadio Friuli.
Antonio Di Natale got the breakthrough for the hosts from the penalty spot eight minutes in before Mauricio Isla doubled the lead prior to the half-hour mark.
A disappointing result for the visitors was compounded by what looked like a potentially serious knee injury to striker Alberto Gilardino.
The 29-year-old will undergo tests on Monday to determine the full extent of the problem.
Lazio have high hopes for this season, and after drawing at Milan in their opening game they were looking for a first win when they hosted Genoa in Rome.
Giuseppe Sculli gave Lazio the lead against the club he left in January but Genoa fought back in the second half to secure a 2-1 victory courtesy of goals from Rodrigo Palacio and Juraj Kucka.
Sebastian Giovinco scored a brace, including a winner in injury time, as Parma beat Chievo 2-1, while a Maxi Lopez penalty proved enough for Catania to beat Cesena in Sicily and Lecce ran out 2-0 winners at Bologna.
In Sunday's early game, Palermo -- conquerors of Inter last weekend -- went down 1-0 at Atalanta in a match played in farcical conditions in Bergamo.
The match was delayed for 40 minutes in the second half to give ground staff a chance to drain a pitch that had become waterlogged in torrential rain, but when the players returned, Palermo were unable to find a reply to German Denis' first-half opener for the hosts.
On Saturday, troubled giants Inter Milan and Roma settled for a goalless draw at the San Siro.
Although Inter halted their spiral of three defeats in three games, including a humiliating home loss to outsiders Trabzonspor in the Champions Legaue, they rarely threatened Roma, who have also had a mediocre start to the season.