Andrea Ranocchia gave the visitor the lead in the 27th minute before Diego Milito added a second just after the half-time break.
Nicolo Cherubin replied immediately, but Esteban Cambiasso scored his first goal of the season minutes later to seal Inter's fifth consecutive win, which keeps the Nerazzurri four points shy of the reigning champion.
Juventus had Arturo Vidal and some controversial refereeing decisions to thank as it edged out Catania 1-0, in the earlier kick-off.
After the host had a goal disallowed in the 25th minute, and the Sicilian side's owner and president Antonio Pulvirenti was sent away from the bench, the home side struggled to maintain a level head and Juve took advantage.
Vidal scored the only goal of the game 12 minutes after the interval, which, unlike Catania's effort, should have been disallowed and it was enough to earn the Bianconeri all three points.
Catania's afternoon was then compounded as it ended the game with 10 men after Giuseppe Marchese was sent off.
Fiorentina needed two wonder goals to see off nine-man Lazio 2-0 in a game riddled with controversial refereeing decisions.
Adem Ljajic drove a rocket into Albano Bizzarri's net after referee Mauro Bergonzi had bizarrely ruled out his tap-in following Mati Fernandez's saved penalty.
Lazio rallied after the interval, but grew frustrated when Stefano Mauri's goal was ruled out for a contentious offside, with both Cristian Ledesma and Hernanes sent to the changing rooms as tempers began to fray.
Vincenzo Montella's men had kept their cool, though, and veteran striker Luca Toni rubber-stamped all three points with a ferocious strike at the death.
Fiorentina's victory sees it climb into fifth place in the league table, halving the six-point advantage of the capital club, which slips to fourth.
Parma rewarded boss Roberto Donadoni's decision to commit his future to the club as three second-half goals saw it to its first away victory of the season, a 3-1 triumph at 10-man Torino.
Elsewhere, Atalanta overcame the dismissal of Federico Peluso to hold off the challenge of Pescara in a goalless contest at the Stadio Adriatico and Daniele Dessena scored the only goal of the game as Cagliari claimed its third successive 1-0 win away to Sampdoria.