Champions Juventus and Napoli pulled clear at the summit of Serie A as they continued their faultless campaigns on Wednesday as Inter Milan fell behind.
Croatia forward Mario Mandzukic scored for Juventus in a 1-0 win over old foes Fiorentina in Turin as Napoli rallied from a goal down to beat Lazio 4-1 in Rome.
Juventus and Napoli have a maximum 15 points after five games, two ahead of Inter Milan who were held 1-1 at Bologna on Tuesday.
Stefan de Vrij had given Lazio a half-time lead over Napoli, but the hosts hit back in the second half with three goals in a four-minute spree including a stunning Dries Mertens strike.
After a tense first half Mandzukic found the opening for Juventus with a diving header after 53 minutes off a Juan Cuadrado cross.
Fiorentina were reduced to ten men for the final half an hour after midfielder Milan Badelj saw red.
"These games teach that to win you have to suffer, 1-0 is a good result," said Juventus coach Massimiliano Allegri ahead of this weekend's Turin derby.
"Napoli, like Inter, Milan and Rome are our rivals. We have to advance calmly, step by step. The derby will be a nice match, we will have a few days to recover."
Napoli routed Lazio in the second half despite Simone Inzaghi's side having gotten off to a flying start with defender De Vrij opening the scoring after 29 minutes.
But injuries to defenders Bastos and then De Vrij turned the tide in favour of Napoli with three goals in the space of a frenetic four minutes.
Senegal's Kalidou Koulibaly got the equaliser after 54 minutes and then Jose Callejon added another two minutes later followed by a superb Mertens effort, before Jorginho added a fourth from the spot as the clock ticked.
Skipper Mauro Icardi rescued a 1-1 draw for Inter Milan at Bologna on Tuesday that ended his side's perfect start to the season.
Amid an avalanche of 28 goals, all the Champions League candidates were on form, expect Lazio who sitting are sixth.
AC Milan are fourth after beating promoted SPAL 2-0 thanks to two penalties as Torino struggled to a 3-2 win over Udinese and are fifth.
AS Roma outclassed promoted Benevento 4-0 as Eusebio Di Francesco's side followed on from last weekend's 3-0 win over Verona to move seventh.
Edin Dzeko hit a brace in either half and provoked own goals by Fabio Lucioni (35) and Lorenzo Venuti (74) at the Stadio Vigorito.
The Bosnian hit-man had no problem infiltrating a weak Benevento defence which leaked six goals last weekend against Napoli, scoring from the right at 22 minutes and left at 52.
"Dzeko did well, he could have scored more. I loved his spirit of sacrifice," Di Francesco added.
"This team was meant to be challenging for the Scudetto at the start, then after two games people said we'd be fighting for fourth or fifth, so really it's just meaningless chatter," he said of title talk.
Crotone and Benevento are already relegation candidates with a point between them as they sit rock bottom.