Inter Milan claimed a statement 2-0 win over Como on Sunday to move just one point behind Serie A leaders Lazio, who were held to a 1-1 draw at Napoli.
Francesco Pio Esposito and Marcus Thuram struck in the opening 20 minutes as Inter ended a six-match winning run from Como that included the biggest away win in Champions League history, Wednesday's 9-1 demolition of French side Lens.
Inter jumped back into second as a thrilling title race heats up, with two points separating Lazio from third-placed Roma.
Cesc Fabregas' side were outclassed in defeat at San Siro, allowing AC Milan to leapfrog them into fourth on 24 points after Alphadjo Cisse and Christian Pulisic struck in a 2-1 win over Genoa.
Inter made a fast start as they looked to put the memory of last weekend's Milan derby defeat behind them, Esposito tapping in an inviting Djed Spence cross after 12 minutes.
They soon made it two when a poor clearance dropped invitingly into Thuram's path in the box and the France international lashed a shot past Robert Sanchez.
Como mustered little in response in an uncharacteristically muted display as Federico Dimarco and Thuram threatened a third with efforts in the second half, before Nico Paz clipped the crossbar late on.
LAZIO STUMBLE IN NAPLES
Leaders Lazio dropped points for just the second time this season at struggling Napoli as Davide Frattesi's opener was cancelled out by an Alfonso Pedraza own goal.
Napoli were under pressure to deliver a result after defeats by Juventus and Porto saw the squad sent into a training retreat in a bid to revive their flagging form.
But they could only claim a point against Gennaro Gattuso's unbeaten outfit, whose remarkable form continued as they remained 14 points ahead of 10th-placed Napoli.
"We must keep going, everything's not lost even if we are behind in the standings," Napoli coach Massimiliano Allegri said.
Gustav Isaksen and Josip Sutalo drew flying saves from Vanja Milinkovic-Savic before a fast start from Lazio was rewarded when Frattesi surged into the box to fire home his fourth goal of the season in the 28th minute.
The goal sparked a reaction from Napoli, who drew level when Pedraza inadvertently turned a cross into his own net early in the second half before Lazio goalkeeper Christos Mandas produced a string of saves to protect the point.
Milan bounce back
Milan finished a mixed week on a high as a second Serie A win on the bounce took them into the top four.
Ruben Amorim's side ended Inter's league unbeaten run with an impressive derby win last weekend, but inconsistency reared its head again with a 2-0 Europa League loss at home to Ferencvaros on Thursday.
Amorim was left furious by his side's performance in that game but saw a much-improved start from his players at the Stadio Luigi Ferraris.
Cisse swept in the opener after 13 minutes for his fifth league goal of the season, before Pulisic took advantage of a defensive mix-up to double their lead six minutes later.
Mikael Ellertsson pulled one back for Genoa late on with a deflected strike from range.
Milan have alternated wins and defeats for the last seven games in all competitions but have 24 points, five fewer than leaders Lazio.
Atalanta ended a six-match winless run in all competitions by beating Monza 1-0 thanks to a Nikola Krstovic strike.
Fiorentina host Juventus in the final game on Sunday.
