ROME (AP) Inter Milan's offseason overhaul is paying off perfectly.

Four rounds into Serie A, the squad coached by Roberto Mancini is the only perfect team in Serie A - the club's best start in 13 years.

And with four-time defending champion Juventus and Roma already paying the price of the Champions League with injuries to key players, Inter appears fresher and is developing into an unexpected title contender.

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Having finished a dismal eighth last season, Inter failed to qualify for Europe and went on a spending spree instead.

New players like Stevan Jovetic, Ivan Perisic, Felipe Melo, Geoffrey Kondogbia, Miranda, Jeison Murillo and Alex Telles are making an immediate impact.

A solid defense has conceded only one goal and allowed Inter to win each match by a one-goal margin.

While the attack is still a work in progress, last season's Serie A scoring leader Mauro Icardi scored his first goal of the season in Sunday's 1-0 win over Chievo Verona and is learning to play alongside Perisic and Jovetic.

Felipe Melo and Kondogbia have added physicality in midfield, something that Melo was asked about after Sunday's match.

''I never tackle with the aim of breaking a leg,'' Melo responded. ''But football is a contact sport. If you don't want to have contact with your opponent you can always choose to play tennis.''

In Wednesday's midweek round, Inter hosts Hellas Verona, which will be without injured forward Luca Toni.

The action begins Tuesday with AC Milan at Udinese.

On Wednesday, it's: Carpi vs. Napoli; Chievo Verona vs. Torino; Fiorentina vs. Bologna; Juventus vs. Frosinone; Lazio vs. Genoa; Palermo vs. Sassuolo; and Sampdoria vs. Roma.

Thursday's lone match features Empoli vs. Atalanta.

Here are some things to know about this week's Italian league matches:

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VULCANIC NAPOLI

After failing to win its opening three matches of the season, Napoli erupted to outscore the opposition 10-0 in its last two games.

First, Napoli beat Club Brugge 5-0 in the Europa League last week then the southern club routed Lazio by the same score in Serie A on Sunday.

It was the perfect response to wide-ranging criticism - even from former Napoli great Diego Maradona - of new coach Maurizio Sarri.

''Our approach was perfect,'' Sarri said. ''But I don't think we've resolved all of our problems, just like I wasn't worried at the start of the season.''

Napoli forward Gonzalo Higuain, who missed a penalty last season against Lazio that could have secured his club a spot in the Champions League playoffs, scored twice Sunday.

''We want to bring Napoli back into the Champions League, where it deserves to be,'' Higuain said.

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SAN SIRO FOREVER

AC Milan has scrapped plans for a new stadium, deciding to continue sharing the San Siro with Inter.

Earlier this year, Milan had unveiled tentative plans for a new 48,000-seat stadium with a retractable roof to be built next to the club's recently opened headquarters in the Portell-Fiera area of Milan.

The new stadium was backed strongly by Milan vice president Barbara Berlusconi. But club president Silvio Berlusconi can't be torn away from the San Siro.

''(Barbara) understands why we had to backtrack,'' Silvio Berlusconi said. ''I'm in love with the San Siro. ... I used to enter the San Siro holding my father's hand and he would make me stay all small so he would only have to pay one ticket. The San Siro has a place in my heart.''

In May, the San Siro will host this season's Champions League final.

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TOUGH TORINO

With a veteran coach in the 67-year-old Giampiero Ventura and a veteran striker in the 32-year-old Fabio Quagliarella, Torino is off to its best start in more than 20 years.

The ''Granata'' - maroons - are in second place, two points behind Inter, with three wins and a draw from the opening four rounds.

Quagliarella scored twice in Sunday's 2-0 win over Sampdoria, giving him four goals for the season.

Brazilian winger Bruno Peres has also been in fine form - helping the squad forget standouts like current Sevilla forward Ciro Immobile and Manchester United fullback Matteo Darmian, each of whom departed over the past two years.

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Andrew Dampf can be followed at www.twitter.com/asdampf