Inter Milan pulled clear at the top of Serie A after coming from behind to beat Bologna 3-1 on Saturday, while Napoli's torrid start continued with a shock defeat by Venezia.
The champions came in for criticism after a disappointing 4-3 midweek Champions League defeat against Club Brugge, but bounced back to move three points clear of second-placed Lazio, who face Juventus in Turin on Sunday.
"Our strength is the group and the quality of the players," Inter assistant coach Aleksandar Kolarov told DAZN, speaking after head coach Cristian Chivu reportedly lost his voice.
"We don't have anything to prove to anyone except ourselves. We want to be more intense with and without the ball."
Napoli, meanwhile, slumped to their fifth defeat in all competitions to remain ninth as bottom side Venezia picked up their first points of the season on new head coach Davide Nicola's debut.
Bologna, fresh from claiming their first win of the season against Lecce, started brightly at the Stadio Renato Dall'Ara as Tommaso Pobega fired them in front after 10 minutes before hitting the bar with a powerful shot.
But Inter, shorn of injured top scorer and captain Lautaro Martinez after he was ruled out for a month, responded through a towering Marcus Thuram header and would have gone in at the break in front were it not for a superb Lukasz Skorupski save on Francesco Pio Esposito.
Chivu's substitutions proved decisive as Carlos Augusto scored within a minute of coming on midway through the second half, before turning provider for fellow replacement Ange-Yoan Bonny late on.
Inter will now turn their attention to trying to pick up their first Champions League points at home to Shakhtar Donetsk on Wednesday.
NICOLA'S DREAM DEBUT
In Venice, new Venezia head coach Nicola masterminded a shock 1-0 win over struggling Napoli on debut as Kevin De Bruyne had a penalty saved.
Renowned survival specialist Nicola was appointed during the week to replace sacked coach Giovanni Stroppa after last season's Serie B champions failed to pick up a single point in their opening six games.
He made an instant impact as Akor Adams struck the winner early in the second half to seal Venezia's first Serie A win over Napoli since 1942.
It marked a second defeat in a row for Massimiliano Allegri's side after their midweek Champions League loss at Villarreal, and the first time in 25 years that Napoli have lost five of their first nine games in all competitions.
Next up for Napoli is the visit of Bodo/Glimt in the Champions League on Tuesday.
"In football you get moments like this and there is only one way out: keep working seriously and professionally, be more focused and turn this disappointment into anger," Allegri told a press conference.
"It's up to us to turn this situation around, starting with the Champions League."
A flat game came to life early in the second half when Nigeria international Adams latched on to a long ball and beat Alex Meret with a deflected strike in the 49th minute.
Allegri responded by bringing on rested stars Rasmus Hojlund and De Bruyne and the Danish striker immediately threatened when Juan Jesus denied him a tap-in with a superb goal-line block.
Hojlund won a penalty for Napoli midway through the second half when he was hauled down in the box by Matias Moreno, but De Bruyne's spot-kick was well saved by Filip Stankovic low to his right.
The Venezia goalkeeper, son of former Inter midfielder Dejan Stankovic, was decisive in the closing stages with a string of saves, including spectacular stops to deny Stanislav Lobotka and Alisson Santos.
Napoli are ninth after picking up 10 points from their first seven games, while Venezia remain bottom with three points.
Later on Saturday, Roma will look to leapfrog Lazio into second place when they host Genoa.