Inter's consolation came from Mauro Icardi, who marked his return from suspension with a goal, although defeat leaves Stefano Pioli's team in sixth - two points below Lazio in the Europa League qualifying spot.

Nainggolan gave Roma the lead early in the first half when he cut in from the left and curled a shot into the top-right corner of Samir Handanovic's goal.

The visitors doubled their lead 10 minutes into the second half when Nainggolan finished off a Roma counter attack with a rising shot from outside the area which gave Handanovic no chance.

Inter had dominated for much of the second half but failed to take their chances until Icardi finished at the far post from Ivan Perisic's low cross across the face of the Roma goal with nine minutes to go.

But just three minutes later Roma sealed the win when Perotti stroked home a cool finish from the penalty spot after Gary Medel had brought down Edin Dzeko.

Earlier in the day, Lazio boosted their hopes of European qualification with a 1-0 victory at home to Udinese.

Italy international striker Ciro Immobile grabbed the only goal of the game from the penalty spot after Brazilian defender Samir was adjudged to have handled in the box.

Victory for the Rome club was their fourth in five games to leave them a point behind fourth-placed Atalanta.

AC Milan also had to rely on a goal from the penalty spot as they finished 1-0 winners at Sassuolo.

Colombia international Carlos Bacca converted the spot-kick midway through the first half after Andrea Bertolacci went down as he was challenged by Federico Peluso and Alberto Aquilani.

Sassuolo striker Domenico Berardi had earlier missed a penalty at the other end following Juraj Kucka's foul on Alfred Duncan.

In the first game of the day, Fabio Quagliarella struck a last-minute equaliser as mid-table Sampdoria dented Palermo's survival hopes by snatching a 1-1 draw.

The third-bottom hosts had looked on course for just a third win from 21 league matches thanks to Ilija Nestorovski's first-half penalty.

Second-bottom Crotone also had a disappointing afternoon as they surrendered the lead to lose 2-1 at home to Cagliari.

Romanian midfielder Adrian Stoian opened the scoring but the visitors responded with goals from Joao Pedro and Marco Borriello.

Elsewhere, bottom club Pescara were beaten 2-0 at Chievo, while Manchester City loanee Olivier Ntcham struck in added time to earn Genoa a 1-1 draw with 10-man Bologna.