Fiorentina coach Paulo Sousa believes his side can maintain their excellent start to the season after returning to the top of Serie A for the first time since 1999.

Internazionale’s perfect record was left in tatters on Sunday after Fiorentina triumphed 4-1 at San Siro courtesy of a hat-trick from Nikola Kalinic and Josip Ilicic’s penalty. Mauro Icardi netted a consolation goal for 10-man Inter on the hour mark.

“Football is like this in Latin countries, it goes from zero to 80,” Sousa said.

“I already said there were other teams who invested heavily for that, but I won’t hold back either, as we have the quality to face every match knowing we can win.

“I told the lads from the start I want a team always ready to take on anyone, always maintaining our approach.

“We have principles of football that we work hard on and as time goes on this will give us more confidence going forward.”

Sousa added: “Being here and working with this group is wonderful. 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 their first five Serie A matches but were 3-0 down after 23 minutes in a shambolic first half for the home side, who also had Joao Miranda sent off in the 31st minute.

“Nothing changes for us,” Inter’s 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.. Inter and Fiorentina both have 15 points, two more than Torino after they held on for a 2-1 win over Palermo despite ending the match with nine men.

Sassuolo, who drew 1-1 against Chievo Verona, are a point further back. Lazio also have 12 points after they 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 Milan lost 1-0 at Genoa.