Napoli went top of Serie A after a come from behind 2-1 win over struggling Juventus as Fiorentina cruised past 10-man Reggina 3-0.

Juve lost for the second match in a row on Saturday and have now gone four Serie A games without a win, increasing the pressure on coach Claudio Ranieri. He denied, however, that his job could be on the line or that his team were in crisis.

"Do I feel secure? Of course I am. This isn't a crisis, sure we're having a tough time but we're not talking about a crisis here," he insisted.

With just two wins from seven matches Juve are down in the bottom half and certain to drop even further following Sunday's matches.

Napoli's lead at the top will likely last less than 24 hours but their victory was reward for a disciplined performance and thrilling comeback.

Slovakian goalscorer Marek Hamsik is not getting carried away by their lofty standing. "We're delighted to be first but our aim is simply to improve on last season's finish (eighth)," he said.

"We definitely want to be in the UEFA Cup. Juventus are a great team but they had some big players out and had some problems."

Juve had the better of the first period and took the lead in Naples a quarter of an hour into the second half, but once again failed to hold onto their advantage.

Brazilian forward Amauri nipped in front of his marker to volley home a right-wing cross from Denmark midfielder Christian Poulsen on 61 minutes.

But just three minutes later the hosts were level as Juve's back line were caught napping, allowing Hamsik to convert Ezequiel Lavezzi's cross at the back post.

Lavezzi then hit the winner 10 minutes from time, bundling his way into the box and then sending former Arsenal goalkeeper Alex Manninger the wrong way with a crisp right foot finish.

Fiorentina are just a point behind Napoli following their third straight victory, proving they have overcome their early season troubles when they lost their first two away matches.

A penalty from Giampaolo Pazzini and an Alberto Gilardino brace secured the three points and coach Cesare Prandelli was a relieved man after the final whistle.

"We were worried about this match because after the international break it is difficult to re-motivate the team," he said.

Reggina remain rooted in the relegation zone on just two points and finished the match with 10 men after goalkeeper Andrea Campagnolo was harshly sent off in the first half.

That moment proved the turning point in a game where Fiorentina dominated but had struggled to break down stubborn opponents who defended in numbers.

Pazzini reached a Zdravko Kuzmanovic through ball ahead of Campagnolo and prodded the ball past him before going down under the goalkeeper's challenge, leading to Campagnolo's sending off.

Pazzini converted easily from the spot five minutes from the break and it was plain sailing there on for Fiorentina.

Gilardino came on midway through the second period to replace Pazzini and within three minutes he'd doubled the home side's advantage, beating the offside trap and running onto a Riccardo Montolivo through ball before firing low past substitute goalkeeper Christian Puggioni.

Gilardino bagged his second nine minutes from time after some comedy goalkeeping from Puggioni, nodding the ball over the stranded keeper and slotting the ball into an empty net.