MILAN - Zlatan Ibrahimovic scored one and set up the other as Inter produced a commanding second-half display to see off Lazio at the Meazza.
The victory sees José Mourinho's Serie A leaders open up a double-figure ahead of Sunday's fixtures, which see second-placed AC Milan away to Catania and Juventus at home to Lecce.
Mourinho rang in the changes after last weekend's defeat to Napoli. With Stankovic and Balotelli out suspended, the Portuguese opted for 4-3-3 with Mancini and Figo wide on the wings in support of Ibrahimovic. Santon returned in his right-back slot while Muntari shrugged off a muscular problem in time to start alongside Zanetti and Cambiasso in midfield.
Lazio were without a host of regulars, with Pandev, Dabo, Diakite, Mauri, Cribari and Simone Inzaghi not making the trip to Milan. Delio Rossi started with his usual 4-4-2, with Zarate and Rocchi up front.
After a weak shot from Rocchi and a decent free kick from Kolarov, it was Argentine fantasista Zarate who posed the main threat in the first half with some trademark mazy runs, one costing Samuel a yellow card and another forcing a tipped save from Julio Cesar.
Inter, though, had the better chances of the opening forty-five and Mancini fired wide from an inviting postion as early as the third minute. Ibrahimovic headed narrowly wide a cross from an in-form Figo before the half-hour, with Muntari getting in behind the Lazio defence before sending wide his flicked header from Ibrahimovic's centre.
With Inter struggling to gain the upper hand, Mourinho brought on two pairs of fresh legs eleven minutes after the restart, replacing Mancini with Crespo and Santon with Vieira.
Two minutes later Ibrahimovic broke the deadlock, powering into the box and sidestepping Rozenhal before sending an unstoppable shot past Muslera.
Muntari celebrated his return with Inter's second goal when he raced on to Ibrahimovic's superb through pass and fired beyond a hapless Muslera.
Chivu miskicked in front of goal as Ibrahimovic thought he had laid on a third goal, and the Swede severely tested Muslera with a fierce drive as Inter could easily have racked up a four-goal advantage.
To their credit, Lazio went down fighting as Rossi's men attacked the left wing in a final period marred by a spate of bookings, one of which will cost Ibrahimovic his presence against Chievo next weekend.
Inter 2-0 Lazio (HT: 0-0)
Scorers: Ibrahimovic 58, Muntari 70.
Inter: 12 Julio Cesar; 39 Santon (14 Vieira 56), 2 Cordoba, 25 Samuel, 26 Chivu; 4 Zanetti, 19 Cambiasso, 20 Muntari (16 Burdisso 75); 7 Figo, 8 Ibrahimovic, 33 Mancini (18 Crespo 56).
Subs not used: 1 Toldo, 9 Cruz, 11 Jimenez, 23 Materazzi.
Coach: José Mourinho.
Lazio: 86 Muslera; 32 Radu (2 Lichtsteiner 72), 13 Siviglia, 22 Rozenhal, 3 Kolarov; 5 Brocchi, 24 Ledesma, 8 Matuzalem, 81 Del Nero (17 Foggia 63); 18 Rocchi, 10 Zarate (20 Kozak 85).
Subs not used: 1 Carrizo, 23 Meghni, 29 De Silvestri, 68 Manfredini.
Coach: Delio Rossi.
Referee: Paolo Tagliavento (Terni).
Booked: Samuel 26, Del Nero 44, Vieira 82, Ibrahimovic 86, Matuzalem 86, Ledesma 88, Chivu 90+1.