Inter Milan kept their flawless start to the season intact by edging Cagliari 1-0 away, while last season's runners-up Napoli fell further behind following a surprising 2-1 home defeat to Como. Meanwhile, Lazio mirrored Inter's trajectory with another narrow 1-0 triumph over Genoa at the Stadio Olimpico.
Davide Frattesi continued his strong form by netting the decisive 25th-minute goal for a Lazio squad now guided by former Italy boss Gennaro Gattuso. Following these results, Inter, Lazio, AC Milan, and Juventus share the early summit with maximum points from their opening two fixtures, sitting just ahead of Como and Udinese. Napoli are stalled on three points as the second matchday concludes with Lecce hosting AS Roma and Atalanta facing Bologna.
Despite controlling proceedings in Cagliari, Inter struggled to turn their dominance into a comfortable cushion. Hakan Calhanoglu broke the deadlock after nine minutes with a precise long-range strike that caught goalkeeper Elia Caprile flat-footed. Inter wasted several opportunities to extend their lead before the break, with Lautaro Martinez firing narrowly wide, Manuel Akanji heading past the post, and Federico Dimarco testing Caprile with a sharp reflex stop.
After the interval, Caprile denied Pio Esposito, while Inter goalkeeper Josep Martinez intervened to stop dangerous crosses. Cagliari nearly punished the visitors' profligacy late in the game, but defender Yann Bisseck made a vital goal-line block to deny Michel Adopo's fierce drive and secure the hard-fought victory.
Elsewhere, Como proved their historic fourth-place finish and subsequent Champions League qualification were no fluke by stunning Napoli in their own stadium. Cesc Fabregas's visiting side drew first blood in the 17th minute when Assane Diao beat Mathias Olivera on the flank and delivered a cross for Martin Baturina, who finished brilliantly on the turn.
Although Noa Lang squandered a golden chance to equalize by heading over from close range, Napoli soon leveled when Rasmus Hojlund manufactured space on the edge of the box and drilled a low shot into the far corner. Como reclaimed the lead just four minutes later after defensive miscommunication allowed Baturina to intercept an underhit backpass, setting up Tasos Douvikas to slot home his second goal of the campaign.
Despite Napoli manager Massimiliano Allegri introducing a triple-substitution early in the second half in search of a spark, the visitors resolutely defended their lead to secure all three points.