The blank meant Napoli missed a golden opportunity to close the gap on Serie A leaders Juventus to just two points.
Goalkeeper Sergio Romero was in particularly inspired form as Delio Rossi's men claimed another valuable point in their mission to book a second season in the top flight, with Samp spurning several chances to win through young striker Mauro Icardi.
Napoli's forward line suffered from a rare lack of cutting edge and ended the day four points behind Juve, who were surprised by a 1-0 defeat to Roma.
In Sunday's late game, Fiorentina rejoined the hunt for a Champions League place with a resounding 4-1 win over Inter Milan at the Stadio Artemio Franchi.
Two goals apiece from Adem Ljajic and Stevan Jovetic earned the Viola all three points, although Antonio Cassano did restore some pride for Inter with a fine consolation goal in the 86th minute.
Catania, too, are back in contention for a European berth after edging a third consecutive home victory in downing struggling Bologna 1-0. Sergio Almiron broke the deadlock just before half-time and the Elefanti held on to wrest seventh place back from Roma.
Udinese, meanwhile, lost ground on their European rivals after two gilt-edged chances to force a draw went begging at the end of a 1-0 defeat at Genoa. Davide Ballardini earned his second win since replacing Luigi Del Neri as Genoa boss when Juraj Kucka nodded the hosts ahead in the first half.
Two goals from Marco Sau lifted Cagliari away from the relegation zone and left Pescara in real danger as the Sardinians won 2-0 at the Stadio Adriatico. Pescara ended the game with 10 men with Vladimir Weiss sent off in stoppage time as the home fans made their feelings heard.
Elsewhere, an 87th-minute goal by Valter Birsa guided Torino to a 2-1 victory as they won for the first time in four Serie A games. The Granata took the lead through Alessio Cerci just before half-time but German Denis equalised from the penalty spot, with Birsa slotting home Matteo Darmian's cross to win it.