(CNN) -- New signing Diego inspired Juventus to a second successive win of the new Italian Serie A season, beating Roma 3-1 at the Stadio Olimpico on Sunday.
Juventus hero Diego gives Roma goalkeeper Julio Sergio no chance with one of his two goals.
The Brazilian scored twice to open his account for the Turin giants, while his compatriot Felipe Melo added a third goal in injury-time to continue coach Ciro Ferrara's perfect start since being appointed on a full-time basis in the summer.
Diego, who joined from German club Werder Bremen created an early chance for Tiago, but Julio Sergio saved well from the Portuguese midfielder's header.
However, the Roma goalkeeper could not prevent Diego breaking the deadlock soon after in the 25th minute with a fierce right-footed strike.
The capital club hit back 10 minutes later as Italy midfielder Daniele de Rossi stunned Juve keeper Gianluigi Buffon with a long-range effort.
Sergio did well to keep out Amauri's header from another Diego cross, then the forward was denied again just before halftime -- this time by the woodwork.
Roma still had time to squander a chance to go ahead before the interval as captain Francesco Totti was unable to beat Buffon when clear on goal.
But it was last season's runners-up Juve who took the lead again in the 68th minute when Vincenzo Iaquinta set up Diego for another clinical finish, then Totti beat Buffon with a right-foot effort which rebounded to safety off the far post.
With the home side pouring forward in a bid to avoid a second straight defeat, midfielder Melo found space on the counter-attack to seal victory in time added on.
In Sunday's other matches, Sampdoria triumphed 3-1 against Udinese for a second successive victory and Genoa won 1-0 at second-bottom Atalanta to also sit on six points along with Lazio, who won 2-1 at Chievo despite having Emilson Cribari sent off.
Fiorentina beat Palermo 1-0 at home, Cagliari were beaten 3-1 by visiting Siena, Napoli ran out 3-1 winners at home to Livorno and Parma defeated Catania 2-1.
Genoa, who beat Roma 3-2 last weekend, won thanks to a header from defender Emiliano Moretti on the stroke of half-time.
Lazio's summer signing Julio Cruz netted both goals against Chievo, the first from the penalty spot after he was fouled by Santiago Morero four minutes before halftime.
The former Inter Milan player pounced for his second on 53 after Chievo goalkeeper Stefano Sorrentino could not hold Mauro Zarate's fierce shot, then Cribari received his second yellow card with 20 minutes to play.
Chievo, who led in the 16th minute through Sergio Pellissier's, could not take advantage of their extra man as substitute Simone Bentivoglio hit the crossbar.