Ciro Immobile scored a hat-trick as Lazio stunned AC Milan 4-1 in Serie A, while city rivals Inter joined Juventus at the top with a 2-0 win over SPAL on Sunday.
Luciano Spalletti’s Inter were too strong for promoted SPAL in the San Siro and joined Juventus on maximum nine points after the champions beat Chievo 3-0 on Saturday.
Simone Inzaghi’s Lazio ran riot over the Chinese-owned Milan with an on-fire Immobile scoring three goals in the space of 10 minutes, including a penalty, in a match delayed for an hour due to torrential rain in the capital.
Riccardo Montolivo pulled one back for the visitors off a deflected Hakan Calhanoglu free-kick, but Vincenzo Montella’s side fell to their first defeat in three games.
Lazio remain unbeaten this season and overtake Milan to move third with seven points.
Earlier, Inter Milan’s Mauro Icardi added to his Serie A tally with a 27th-minute penalty, giving him a fifth goal of the season after braces in the opening two games.
The spot-kick was awarded after the intervention of the video assistant referee (VAR), after Joao Mario was tripped inside the box with Icardi slotting in.
Ivan Perisic sealed the victory after 87 minutes with a powerful volley into the top corner.
Inter and Juventus could be joined at the top by Napoli later Sunday, when they visit Bologna.
After two easy matches against Crotone and Cagliari, Milan got a reality check against Lazio.
Immobile’s first was from a penalty on 38 minutes, and four minutes later he added a second with a volley off a Senad Lulic cross.
The Italian international then got his third six minutes later and quickly assisted Luis Alberto for the fourth.
Fiorentina bounced back from successive defeats with their first win of the season — a 5-0 rout at Verona.
Argentine striker Giovanni Simeone, son of Atletico Madrid coach Diego Simeone, scored his first goal for the Tuscany club after two minutes.
Elsewhere, Atalanta won 2-1 at home against Sassuolo while Cagliari achieved their first win in their new stadium, beating Crotone 1-0, and Udinese defeated Genoa 1-0.
Paulo Dybala inspired Juventus to victory over Verona side Chievo ahead of next week’s Champions League opener at Barcelona, with the game between Sampdoria and Roma in Genoa postponed because of adverse weather conditions.