Juventus’s hopes of dropping Inter Milan virtually out of the Serie A title race suffered a setback after it went down to a shock 2-1 home defeat to Sampdoria on Sunday.
Inter had been stunned 3-0 by Udinese in the day’s early match, handing Juventus the chance to take its lead to a massive 12 points.
But after Sebastian Giovinco had given the Bianconeri a 24th minute lead from the penalty spot the host was stunned by a double from Emanuel Icardi.
At the halfway stage Juventus, on 44 points, now has a five-point lead over Lazio, which had secured a late 2-1 win over Cagliari on Saturday.
Fiorentina had hoped to close the gap to Lazio to one point, as well as further distance fourth-placed Inter, only to suffer a shock 2-0 defeat at home to visiting Pescara.
La Viola finished the day in fourth place after Napoli moved up two places to third thanks to a superb 4-1 win over Roma at the San Paulo.
Napoli’s 12th win of the campaign came largely courtesy of an Edinson Cavani hat-trick, which put the Uruguayan on 16 league goals and two clear of AC Milan’s Stephan El Shaarawy (14) at the top of the scoring charts.
Giovinco stepped up to convert Juve’s penalty with relative ease after Claudio Marchisio was adjudged to have been fouled in the box.
But Sampdoria came fighting back in the second half and when Icardi broke free in the 52nd minute he beat Gianluigi Buffon with an impressive angled strike from the edge of the area.
Italy ‘keeper Buffon was then left clutching at thin air when, from a tight angle, the Argentine blasted the ball inside the near post and into the roof of the net on 68 minutes.
Barcelona cruised to a 4-0 win over Espanyol in the Spanish league on Sunday.
All of Barcelona’s goals came in the first-half.
Italian league: Udinese 3 (Di Natale 64, 79, Muriel 75) bt Inter Milan 0; Chievo 1 (Cofie 37) bt Atalanta 0; Fiorentina 0 lost to Pescara 2 (Jonathas 57, Celik 90+1); Genoa 2 (Borriello 57, 73) bt Bologna 0; Juventus 1 (Giovinco 24) lost to Sampdoria 2 (Icardi 52, 68); AC Milan 2 (Bojan 67, Pazzini 80-pen) bt Siena 1 (Paolucci 87); Parma 2 (Belfodil 62, Amauri 90+2) bt Palermo 1 (Budan 85); Napoli 4 (Cavani 4, 48, 70, Maggio 90+1) bt Roma 1 (Osvaldo 72).
Spanish league: Barcelona 4 (Xavi 10, Pedro 15, 27, Messi 29-pen) bt Espanyol 0.