After splashing out £75 million on Jerome Boateng, Yaya Toure, David Silva and
Aleksandar Kolarov, they will be expected to proceed against the side that finished fifth in their domestic top flight last season.
Speaking to the club's official website, the Italian declared he was not going to be complacent about the ties that will be played on August 19 and 26.
"It will be a difficult game and any team from Romania will provide stiff opposition, particularly on their own ground," Mancini said.
"We will look forward to both legs and obviously look to ensure we move to the group stages of the competition."