Last season’s Golden Boot winner Immobile put Lazio ahead in the 14th minute after Manuel Lazzari dispossessed a dithering Roger Ibanez and set up the striker’s 12th goal in the current campaign.
Nine minutes later, the fast winger Lazzari had again the better of the Brazilian defender and squared for Luis Alberto’s shot into the far corner.
Lazio remained in control and after the break Roma goalkeeper Pau Lopez saved attempts from Sergej Milinkovic-Savic, Felipe Caicedo and Immobile.
But he stood no chance on Luis Alberto’s drive in the 67th minute.
The Spaniard sealed the Laziali’s victory by firing clinically from outside the penalty box into the right corner.
Pepe Reina, himself a Spaniard keeping goal for Lazio, blocked a late effort from the Giallorossi captain Edin Dzeko with five minutes to go.
“For us it was very important to win,” Luis Alberto said, “because in Serie A we had a glum period. But we have been improving [with wins] in the last three games. We have improved a lot and today we confirmed it.”
Lazio, who qualified to meet holders Bayern Munich in the last 16 of the Champions League, moved to seventh place in Serie A and are now three points behind the third-placed Giallorossi.
Champions Juventus are fourth, one point behind Roma and with a game in hand, before Sunday’s classic against second-placed Inter Milan.
Leaders AC Milan, now sitting three points clear of Inter, meet Cagliari on Monday.
