A superb first-half strike from Gonzalo Higuain ended Lazio`s six-game unbeaten run and helped Napoli up to third place in Serie A after a precious 1-0 win away to the Biancocelesti on Sunday.
Lazio had climbed up to third thanks to an impressive run of performances in which Felipe Anderson had underlined his credentials as a potent strike force for Stefano Pioli`s side.
However the Brazilian forward, who had scored five times in as many successive games, was ruled out with knee ligament damage last week. On Saturday Lazio captain Stefano Mauri also joined the side`s growing injury list, while goalkeeper Federico Marchetti was also suspended.
Napoli were looking to get back on track following a 3-1 home defeat to leaders Juventus last week, and Higuain gave Rafael Benitez`s side the perfect start with a fine strike in the 18th minute.
Sent through the right side of midfield, the Argentinian made the most of the space given to him by defender Stefan Radu to fire an angled drive inside Etrit Berisha`s near post and into the roof of the net.
Higuain celebrated scoring his 10th goal of the campaign, which means he is now one short of league-leading Juventus striker Carlos Tevez, by holding up the jersey of injured fellow forward Lorenzo Insigne.
Lazio spurned a series of chances to pull level, Lucas Biglia firing a long-range effort wide, while Marco Parolo saw his header from a free kick beat Rafael but came off the `keeper`s crossbar.
Pedro Luis Cavanda then volleyed straight at Rafael after being left unmarked in front of goal.
Pioli introduced German striker Miroslav Klose for the start of the second half but it was Napoli who threatened first with Higuain firing a low drive inches wide of Berisha`s far post from the right flank,
Lazio saw their penalty claims waved away when Keita Balde`s shot struck Raul Albiol on the hand and after a counter-attack Higuain saw another effort sail just wide of Berisha`s upright.
Antonio Candreva only got a glancing header to a cross and when the ball fell kindly for Keita the Spaniard lost momentum when he tried to control and his shot was charged down.
Napoli had Kalidou Koulibaly to thank minutes later for blocking Filip Djordjevic`s volley and at the death narrowly missed a chance to double their lead.
Jose Callejon ghosted in at the back post to chest a cross from Marek Hamsik into the net, but Bruno Pereirinha deflected his goalbound effort out of play in timely fashion.