Sampdoria were the surprise early front-runners in Serie A until Wednesday's 2-0 defeat at Fiorentina, a result that saw Inter replace them at the head of the table following a 3-1 win over Napoli.

Inter have been gradually improving since their disappointing opening day draw at home to promoted Bari and a victory at high-flying Sampdoria, just three days before an exhausting Champions League trip to Kazan in Russia, would be a demoralizing blow for the pretenders to their crown.

The omens were good for Inter against Napoli as all three of their goals were scored by new signings and forward pair Diego Milito and Samuel Eto'o showed increasing signs of developing a growing understanding.

Meanwhile, Sampdoria came up short in their first stern test of the season in Florence where they could easily have lost by more.

"It will be a difficult match which we will have to approach with great concentration," said coach Luigi Del Neri.

"Defeats are part of football. I'm sure the team will react in the right way to this setback, although don't forget that it came after a great start to the season. If you react to them in the right way, defeats can help you improve."

Inter will be boosted by the return to the bench of coach Jose Mourinho who sat out a one-match touchline ban on Wednesday.

That did not seem to affect the team too much though and the game was over as a contest after half an hour with Inter leading 3-0.

Inter will need to be wary as Juventus sit only behind them on goal difference in the table and face a home match against Bologna tomorrow.

AC Milan are sit six points off the top having won only two of their first five games. They slumped to a 1-0 defeat at Udinese on Wednesday.

Despite their poor start to the season, which has seen them find the net only three times and only once in their last four matches, coach Leonardo does not seem too worried.

"What we lack is the finishing touch. As for ball retention and the positioning of players, we're there," he said.

"We need to work on our movement and the speed of play in the final third. It's early doors, our problem is not how many points we have after five matches, it's that we need to score more goals."

Milan host unbeaten Bari, who have already left the San Siro with a point once this season when they went to Inter on the opening day of the season.

Meanwhile, former Italy boss Roberto Donadoni is under pressure at Napoli, who sit only one place above the relegation zone after one win in their first five matches. They host little Siena in a game they must win.