Udinese's success kept the surprise package two points behind leading pair AC Milan and Juventus who both won away to stay top with 37 points from 17 games.
Zlatan Ibrahimovic converted a first-half penalty, controversially awarded for a foul by Thomas Manfredini on Alexandre Pato, and set up the second for Kevin-Prince Boateng in Milan's 2-0 win at Atalanta.
Alessandro Matri's first-half goal gave unbeaten Juventus an unconvincing 1-0 win at bottom club Lecce where they were lucky to survive second half pressure in pouring rain.
Matri scored from close range when Massimiliano Benassi failed to hold Mirko Vucinic's low shot from 25 metres after Juve had lost midfielder Fabio Quagliarella to injury early in the game.
Goran Pandev, Edinson Cavani and Marek Hamsik put Napoli 3-0 ahead before Fabrizio Miccoli's consolation for Palermo, where coach Bortolo Mutti's home debut ended with a deafening chorus of jeers from the few fans who stayed until the end.
Stevan Jovetic scored twice, the first a penalty, in Fiorentina's 3-0 win at Novara and Cagliari beat Genoa by the same score, handing Pasquale Marino an unhappy debut with the visitors after he replaced Alberto Malesani following a 6-1 defeat at Napoli.
Genoa's misery continued with a straight red card for Emiliano Moretti before Andreas Granqvist put through his own goal.
In the early match, Udinese's Di Natale opened his account after only 48 seconds when he slid the ball home after Antonio Floro Flores sprang the offside trap and broke down the right.
The hapless Antonioli allowed Kwadwo Asamoah's low, swerving shot to slip under him in the 54th minute in what proved to be the game's turning point.
