Walter Mazzarri's men ran out comfortable winners against the hapless Islanders to collect a fifth consecutive triumph while leapfrogging Udinese into fourth place in Serie A
The hosts raced into a three-goal lead inside the opening half hour thanks to strikes from Marek Hamsik, Paolo Cannavaro and a Davide Astori own goal.
Joaquin Larrivey pulled one back before the break, added another in the 77th minute and completed his hat-trick in injury time.
But unfortunately for the Argentine striker, before then Ezequiel Lavezzi had won and converted a second half penalty and Walter Gargano added a fifth before Christian Maggio completed the rout in the 84th minute to give Walter Mazzarri's side their fifth league win on the trot.
The result ensured Napoli would follow up wins against Chievo, Fiorentina, Inter and Parma with another three points while moving them up to fourth in the Serie A table by leapfrogging Udinese who do not play until they travel to face Novara on Sunday.
Mazzarri took the decision to rest Edinson Cavani with Wednesday’s trip to Chelsea in mind. However, the feared frontman’s absence did not phase Napoli in the slightest as they rounded off a bright start by opening the scoring with just 10 minutes on the clock.
Gokhan Inler fed the ball to Hamsik who took full advantage of a Daniele Conti slip by driving past the grounded Cagliari captain and drilling a low shot beyond Michael Agazzi’s despairing dive from 22 yards.
The visitors’ custodian would have been disappointed not to have kept the strike out, but he certainly could not be faulted with the second, which arrived just nine minutes later.
This time Lavezzi whipped over a tantalising free kick from wide on the right and captain Cannavaro applied the finishing touch with a thunderous downwards header which bounced off the ground then crashed into the net via the crossbar with Agazzi rooted to the spot.
Things just seemed to go from bad to worse as the hosts surged into a three-goal lead on the half hour. A neat exchange on the edge of the area saw Walter Gargano release Lavezzi on the right, and the diminutive Argentine drove to the byline before flashing a dangerous ball across the face of goal which Astori only succeeded in turning into his own net for an unfortunate own goal.
Cagliari coach Davide Ballardini responded to their appalling first 30 minutes by making an immediate change, replacing Radja Nainggolan with Thiago Ribeiro and reshuffling his midfield.
The change seemed to have the desired effect as his side quickly cut the deficit in the 38th minute with a goal which was remarkably similar to Napoli’s second. Conti curled over a free kick from wide on the right and Larrivey rose highest to guide a header into the bottom left-hand corner.
The goal rejuvenated the Rossoblu and they finished the half firmly in the ascendancy, but they could not find a second goal and went in at the break 3-1 down with the proverbial mountain to climb.
The interval came at the wrong time for the Islanders, though, because Napoli once again assumed control after the break and twice came within inches of extending their lead when first Goran Pandev, and then Lavezzi, fired just wide of Agazzi’s left-hand post.
Those misses only delayed the inevitable, however, as Lavezzi dusted himself off after being felled inside the box by Michele Canini in 55th minute and sent Agazzi the wrong way with the resultant penalty to restore his side’s three-goal advantage.
Lavezzi’s night came to an end in the 59th minute when he was replaced – to a rapturous reception from the home crowd – by Cavani.
And the Uruguayan soon made his own mark on proceedings, expertly holding the ball up before rolling into his compatriot Gargano’s path. The midfielder burst onto the perfectly weighted lay off and lashed the ball past Agazzi.
Larrivey headed a Victor Ibarbo cross into the net via the left-hand post in the 77th minute to give the scoreline a measure of respectability, but soon afterwards Maggio latched on to Pandev’s intelligent reverse pass and fired across the goalkeeper to make it 6-2.
Amazingly, Larrivey completed his hat-trick and the scoring with another header deep into stoppage time, but by then the goal was little more than a consolation and a matter of personal pride as his side had been comprehensively beaten.
Napoli return to action March 14 when they travel to London for the second leg of their Champions League round of 16 tie with Chelsea. Cagliari, on the other hand, have over a week off before hosting Cesena in next Sunday’s early kick-off.