|Joel Obi sees red as Inter's domestic woes continue [GALLO/GETTY]
Napoli shot to the top of Italy's Serie A with a controversial 3-0 win at 10-man Inter Milan on Saturday as Claudio Ranieri suffered his first defeat in charge and was sent off at halftime.
Earlier, Bojan, Pablo Osvaldo and Simplicio were on target as fourth-placed AS Roma beat Atalanta 3-1.
After an end-to-end start at Inter the game turned dramatically on an incident four minutes before the break when Joel Obi was handed a second yellow card for bundling over Christian Maggio on the edge of the box.
Julio Cesar saved Marek Hamsik's resulting penalty but defender Hugo Campagnaro followed up to give Napoli the lead.
Ranieri was sent off for remonstrating with the officials as the teams trooped off at halftime.
In a more subdued second period wing back Maggio added a second goal on 57 minutes, lifting the ball over Julio Cesar, before Hamsik slotted home the third with a quarter of an hour to go to seal Napoli's first victory at the San Siro in 17 years.
Inter have only four points from five games while Napoli, who finished third last season, go two points clear of Juventus, Udinese and Roma ahead of Sunday's main programme.
The hosts, without Wesley Sneijder and Diego Milito, edged the opening exchanges at the San Siro with Diego Forlan going closest to scoring after fizzing a low 25-metre drive just wide on 13 minutes.
Despite missing striker Edinson Cavani through injury, Napoli enjoyed plenty of possession in a refreshingly open start and Colombian left back Juan Zuniga headed weakly wide with a back-post header after 19 minutes.
The home crowd then started to jeer when Campagnaro put Napoli in front.
The visitors made it 2-0 when Giuseppe Mascara played an innocuous ball over the top of the Inter defence for the energetic Maggio to outpace substitute Yuto Nagatomo and beat Julio Cesar.
With a disjointed Inter leaving huge gaps at the back, Hamsik ran on to Ezequiel Lavezzi's slide-rule pass to ensure Napoli ended a run of eight straight defeats at Inter.
At the Stadio Olimpico, Roma resisted a second-half fightback from promoted Atalanta to earn Luis Enrique's side their second successive win.
Spanish striker Bojan opened the scoring on 20 minutes, grabbing his first goal in the Giallorossi shirt with a left-foot shot.
Argentine forward Pablo Osvaldo doubled the lead with a cool finish just after the half-hour as Roma dominated the opening period.
The second half was a different story after Argentine forward German Denis halved the deficit with a back-post header from a well-worked corner on 48 minutes.
The home side were then made to defend for long stretches until midfielder Simplicio played a delightful one-two with Miralem Pjanic before finishing neatly on 81 minutes.
"It was a difficult game against the in-form side in the league," Luis Enrique told Sky Sports after Roma's first home win of the season.
"The Denis goal meant we had some difficult moments but we were able to survive. We're improving but we need more patience to be able to dominate possession throughout the match."
Atalanta, docked six points for match-fixing, stayed on four points after suffering their first defeat of the season.