Rudi Garcia's side had drawn their previous four and after Juve won 2-0 at Bologna on Friday night the gap at the top had increased to six points.
Goals from Maicon and Mattia Destro in either half, both from Gervinho assists, secured a much-needed win to halve the deficit.
Juan Vargas had levelled for the Viola just before half-time while Roma had Miralem Pjanic sent off in the 88th minute.
Inter Milan had to be content with a 3-3 draw at home to Parma after Rodrigo Palacio had twice hauled them level.
Palacio (44, 54) cancelled out goals from Nicola Sansone (11) and Marco Parolo (45) and it looked like Inter might even win when Fredy Guarin sent them 3-2 up after 56 minutes.
Sansone (59) quickly replied with his second though to ensure Parma got something for their enterprising performance.
Lazio are still waiting for their first away league win after losing 1-0 at Torino.
Kamil Glik's first-half strike was enough for Torino who have lost just twice in nine league games.
Sixth-placed Hellas Verona halted a run of three successive league defeats with a come-from-behind 2-1 victory against Atalanta.
German Denis scored first after eight minutes but substitute Juan Gomez equalised in the 82nd minute before Jorginho Frello scored the winner from the penalty spot five minutes later.
Marco Sau struck twice inside the final 13 minutes as Cagliari battled back from a goal down to see off 10-man Genoa 2-1.
Alberto Gilardino fired the visitors in front inside 20 minutes but Genoa suffered a setback two minutes before the break when Thomas Manfredini was dismissed for a second caution.
The visitors weathered the Cagliari storm for much of the second half before finally succumbing when Sau opened his account in the 77th minute, before the Italy international bagged the winner in the final minute.
Sampdoria claimed their first win in six games as goals by Eder and Manolo Gabbiadini secured a 2-0 win over Catania in Serie A.
Cyril Thereau (55) scored the only goal of the game as Chievo edged Sassuolo 1-0 to record their third successive victory.