Udinese striker Antonio Di Natale scored his 199th Serie A goal, and the fastest of the season, although it was not enough for his side who lost 4-2 at home to flying Genoa, while AC Milan suffered a shock home defeat against promoted Palermo.
Palermo scored twice in a three-minute first-half spell while misfiring striker Fernando Torres again failed to hit the target for Milan, who are tied for sixth on 16 points after their second defeat of the season.
Third-placed Sampdoria went ahead when defender Angelo Palombo converted a penalty in the 27th minute only for the same player to give one away five minutes later with a foul on Kouma Babacar.
However, Argentina goalkeeper Romero, who saved two penalties in the World Cup semi-final shootout against the Netherlands, denied compatriot Gonzalo Rodriguez.
Luca Rizzo increased with Sampdoria’s lead with an individual goal before Stefan Savic headed one back for the visitors in first-half stoppage time.
Brazilian forward Eder made the game safe for Sampdoria when he burst past three defenders in a run from midfield and slid the ball under Norberto Neto.
Germany forward Mario Gomez came on in the second half for Fiorentina, his first appearances since suffering a thigh injury in September.
Sampdoria have 19 points from 10 games, one ahead of Genoa and Napoli. Juventus lead with 25 points followed by Roma on 22.
Evergreen Di Natale, 37, scored after only 23 seconds when he ran onto Panagiotis Kone’s pass to beat Mattia Perin.
Genoa, who handed leaders Juventus their first league defeat of the season on Wednesday, equalised with a Giovanni Marchese volley and went ahead when Iago Falque pounced on dreadful defending to score from close range.
Udinese were level before halftime when Di Natale’s incisive through ball set up Silvan Widmer to score with an angled drive.
Second half goals from Alessandro Matri and Juraj Kucka gave Genoa the points while Di Natale was centimetres away from his 200th league goal when his shot shaved the post.
Torres, who has managed one Serie A goal since joining Milan this season, shaved the post with a header early on but his side never looked like recovering after falling behind.
Colombia defender Cristian Zapata headed a corner into his own goal in the 23rd minute and Pablo Dybala broke down the left and beat Diego Lopez with an angled shot three minutes later.
Rolando Maran picked up his first point as Chievo coach at the third attempt when they drew 0-0 at home to Sassuolo, while Torino’s match against Atalanta, who have scored only four goals all season, also ended goalless.
(Writing by Brian Homewood in Berne, editing by Pritha Sarkar/Greg Stutchbury)