Inter Milan's perfect record this season was left in tatters on Sunday after Fiorentina triumphed 4-1 at San Siro to move top of Serie A.

Nikola Kalinic scored a hat trick and also won a penalty which Josip Ilicic converted for the fourth-minute opener. Mauro Icardi netted a consolation goal for 10-manInter on the hour mark.

"Being here and working with this group is wonderful," Fiorentina coach Paulo Sousa said. "We have got continuity, playing well at the back as well as up front.

"There are teams which have invested a lot, they have different aims to us, but I am not going to hold back and I continue to say that we can face anyone to win."

Inter had only conceded one goal in its first five Serie A matches but found itself 3-0 down after 23 minutes in a shambolic first half for the home side, which also had Joao Miranda sent off in the 31st minute.

"Nothing changes for us," Inter coach Roberto Mancini said. "We had our feet on the ground already and so this defeat doesn't serve as a lesson to us."

Fiorentina moved above Inter on goal difference. It is the first time the Tuscan side has been top of Serie A since February 1999 — after beating AC Milan.

Inter and Fiorentina both have 15 points, two more than Torino after it held on for a 2-1 win over Palermo despite ending the match with nine men.

Sassuolo, which drew 1-1 against Chievo Verona, is a point further back. Lazio also has 12 points after the capital side came from behind with 10 men to win 2-1 at Hellas Verona for the first time in 24 years.

Marco Parolo snatched Lazio's late winner, minutes after the dismissal of defender Mauricio for a second yellow card.

Udinese also came from behind to win by the same scoreline at Bologna, ending a four-match losing streak, while 10-man AC Milan lost 1-0 at Genoa.

It was first against second at San Siro, with Inter full of confidence after winning its first five matches.

However, it got off to a dismal start as Samir Handanovic conceded an early penalty. The Inter goalkeeper's first touch let him down as he failed to collect a backpass and then barged Kalinic over as he attempted to grab the ball back.

It was the first time Inter had been behind all season and it found itself 2-0 down in the 18th.

Handanovic flew to punch clear Ilicic's effort from distance but it looped up behind him and Kalinic reacted quickest to burst forward and help it in.

"I take my share of the responsibility," Handanovic said. "I made an error with the stop (for Kalinic's first), but the penalty was one that is sometimes given and sometimes not.

"But it was a nightmare evening in all points of view. We need to forget tonight and move forward."

Kalinic doubled his tally five minutes later, sliding in to turn home Marcos Alonso's cross after the Spanish defender had waltzed past Ivan Perisic on the left flank.

Matters went from bad to worse for Inter as any hopes of getting back into the match evaporated with the dismissal of Miranda for hauling down Kalinic after a through ball had sent him clear on goal.

Inter pulled one back when Icardi headed Alex Telles' free kick onto the base of the left post and then tapped home the rebound.

But Fiorentina restored its three-goal advantage in the 76th when Kalinic won a tussle with Davide Santon and found Slovenia's Ilicic, who drew defenders toward him before squaring the ball back for the Croatian to complete his hat trick.

Sassuolo and Chievo Verona missed the opportunity to move provisionally second in Serie A as they drew 1-1 on Sunday.

Alberto Paloschi leveled in the 24th after Gregoire Defrel had given Sassuolo a third-minute lead.

Instead Torino leaprogged both into second, holding on for a 2-1 win over Palermo despite ending the match with nine men.

Udinese also came from behind to win by the same scoreline at Bologna, snapping a four-match losing streak, while 10-man AC Milan lost 1-0 at Genoa.

Both Sassuolo and Chievo knew they could move into second spot for a few hours at least with a win at Mapei Stadium.

Sassuolo got off to the perfect start when Defrel headed in after Albano Bizzarri parried Antonio Floro Flores' strike.

Chievo leveled 11 minutes later as Paloschi's glancing header beat the goalkeeper into the far bottom corner. The goal was only given after several moments of discussion between the officials as to whether Fabrizio Cacciatore had got the final touch, with the Chievo defender - who appeared to be in an offside position - insisting he had kicked the ball after it went over the line.

Television replays showed the decision to award the goal was correct as not only had Cacciatore touched the ball after it crossed the line, but he looked to be just onside on Paloschi's header.

Defrel thought he had restored Sassuolo's lead but he was harshly adjudged to have been offside on Alfred Duncan's pass.

Sassuolo moved level on points with Fiorentina and Torino, one ahead of Chievo.

Torino had suffered its first defeat of the season midweek against Chievo and almost found itself behind five minutes from halftime when Aleksandar Trajkovski's free kick crashed off the crossbar.

Instead it was Torino which went in at the break ahead after Maxi Lopez attempted to reach Cristian Molinaro's low cross and, in trying to stop him, Palermo defender Giancarlo Gonzalez bundled it into his own net.

Marco Benassi doubled Torino's lead with a sensational volley into the far top corner from Maxi Lopez's cross immediately after the break.

Palermo was handed a way back into the match on the hour mark when Molinaro was sent off following a second booking and Gonzalez atoned for his own goal by heading into the opponents' goal 10 minutes later.

Torino went down to nine men a minute from time when Joel Obi was shown a straight red card for a challenge on Franco Vazquez. Palermo almost snatched a point but Aljaz Struna headed Oscar Hiljemark's cross off the bar.

Lazio hadn't won a Serie A match at the Bentegodi since October 1991 but almost got off to the perfect start when it had the ball in the back of the net after three minutes, but play had been stopped for a foul in the box.

Verona took the lead in the 33rd after Juanito Gomez Taleb hit Federico Viviani's free kick onto the bar from two yards out but Per Helander nodded in the rebound to spare his teammate's blushes.

Lazio leveled in the 63rd when Lucas Biglia sent a penalty straight down the middle after Jacopo Sala had brought down Keita Balde Diao, who had come off the bench moments earlier.

Lazio defender Mauricio was shown a second yellow card nine minutes from time but the visitors snatched a winner five minutes later when Biglia took a short free-kick and Marco Parolo drilled it into the bottom left corner.