A legendary player at the Camp Nou, Luis Enrique was appointed as Gerardo Martino's successor in May and Roman's strike in the second half ensured Barca clinched the Colombino Trophy.
Luis Enrique named a youthul matchday squad and swapped the entire XI at half-time - leading to a far from classic encounter.
However, Roman's goal ensured Luis Enrique a positive start to his coaching career with the club ahead of next week's friendly with Nice.
Croatian midfielder Alen Halilovic was among Barca's starting XI for the first half and he had one of the better chances of the first half.
After Dani Neto struck a free-kick narrowly over the crossbar, the former Dinamo Zagreb man unleashed a dipping volley at the hosts' goal that Daniel Sotres was required to save.
The pair, along with Adama Traore, caused problems for Recreativo but were unable to gain a breakthrough before Luis Enrique rung the changes at half-time.
Goalkeeper Jordi Masip made way for Marc-Andre ter Stegen while Ibrahim Afellay and Gerard Deulofeu were also introduced.
Raul Molina and Josmar Zambrano each had good opportunities in quick succession for the second-tier side before Deulofeu, seeking to establish himself in Barca's starting XI for the coming season, helped create the winner six minutes after the hour.
Cutting inside of the left, he beat two defenders and hit an effort at goal. When that was parried by Sotres, Roman was on hand to finish.
Deulofeu continued to be among the action as he and Afellay both forged half chances for Barca while Recreativo struggled to muster any openings of note.
There was enough time for Deulofeu to rattle the underside of the crossbar as Luis Enrique's first outing as Barca boss ended in a narrow win.
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