Dybala was Roma's marquee signing of the off-season, moving to the capital after his contract expired in Turin, but it Bryan Cristante who scored the only goal of the match in the 33rd minute on Sunday.

Mourinho steered Roma to the Europa Conference League title last season, the club's first trophy in 14 years. Having finished sixth in Serie A they will be targeting a top-four finish and a Champions League spot but they are also seen as dark horse for the title -- despite Mourinho downplaying his team's chances.

Dybala almost opened his Roma account in the 23rd minute as he curled a free kick over the wall and bar.

The visitors took the lead 10 minutes later. A Tammy Abraham attempt was charged down but the ball came to Cristante on the edge of the box and he fired through a crowd of bodies into the far bottom corner.

Dybala could have doubled Roma's lead on the stroke of halftime as he ran onto a through ball from the ever-dangerous Nicolo Zaniolo but his effort came back off the right post.

The 28-year-old Argentina international again went close in the second half and almost had an assist as he rolled the ball across to fellow new signing Georginio Wijnaldum to score, but the goal was ruled out for offside.

In the capital, goalkeeper Luis Maximiano was sent off less than six minutes into his Serie A debut but Lazio managed to win 2-1 against Bologna, who were also reduced to 10 men.

Maximiano, who joined from Granada in the off-season, was adjudged to have handled outside the area and the Portuguese goalkeeper was shown a straight red card.

Bologna broke the deadlock in the 38th minute when Mattia Zaccagni kicked opposing forward Nicola Sansone and Marko Arnautovic struck the resulting penalty into the top right corner.

However, the first half ended with the teams in numerical parity after Bologna defender Adama Soumaoro was sent off following a second yellow card, just minutes after his first.

Lazio eventually equalised in the 68th courtesy of an own goal and the turnaround was complete 11 minutes later as Sergej Milinkovic-Savic threaded a ball through for Ciro Immobile to fire between Lukasz Skorupski's legs.

Elsewhere, Spezia beat Empoli 1-0 and Cremonese lost 3-2 at Fiorentina in a disappointing first match back in the top flight since 1996.

Australian Associated Press