Sampdoria's perfect start ground to a halt with Fiorentina's convincing victory at the Stadio Franchi.

The Blucerchiati had never previously won their first four top flight games, so this was an historic run as well as the Serie A leadership and 100 per cent record they were protecting in Florence. Giampaolo Pazzini returned to face the club he walked out on in January, but the Viola were struggling after back-to-back defeats against Lyon and Roma.

Juan Manuel Vargas was back in action after a heel problem, but Adrian Mutu and Dario Dainelli were dropped in favour of Stevan Jovetic and Per Kroldrup. Sampdoria last conquered the Stadio Franchi in 2004, but in the last 11 years there had only been two draws in 1998 and 2008.

There was already controversy in the opening 200 seconds, as Antonio Cassano flicked on a corner for Sebastien Frey's reaction save at the near post, only just avoiding the ball crossing over completely.

After 14 minutes a well-worked move saw Jovetic backheel flick Alberto Gilardino clear on goal, but the Italian pulled his angled drive off target.

Jovetic has been on fine form this season and he opened the scoring. Crosses rained into the box until eventually Marco Marchionni chipped it up for a totally unmarked Jovetic from six yards. The teenager is one of the shortest players in Serie A, but under absolutely no pressure.

Fiorentina wanted a penalty on 29 minutes when Marius Stankevicius appeared to push Jovetic in the back as a cross came in, but the referee waved play on. Within 60 seconds Samp nearly equalised, as Daniele Mannini burst through the Viola defence and fired inches over.

Frey got down for a stunning reaction save on an equally impressive Pazzini volley in this entertaining game.

Jovetic sprung the offside trap on a long ball and performed a divine first touch, but only hit the side-netting with his finish.

Fiorentina seemed to step up the pressure after the break, with Luca Castellazzi needing two excellent saves. First he denied a Vargas solo effort, then Marchionni's fierce volley.

The Viola deservedly made it 2-0 with Gilardino's 110th Serie A goal. Vargas fought his way past Luciano Zauri down the left flank ad crossed for Gilardino's soaring header.

Substitute Mario Alberto Santana wasted the opportunity for the third by firing straight at Castellazzi, as Samp failed to muster a fightback. Samp also went close, as Pazzini at full stretch just failed to get on the end of a Cassano cross.