The lefty went six innings, allowing just two runs over his time on the mound.
Aquino, 24, who broke in with the Rockies organization in 2010, was a reliever for the Orioles last season after playing for several minor league teams the last several years.
“It’s been a tough process. I’ve been through a few organizations right now,” Aquino said through a translator. “But I’m just thankful to the Orioles for this opportunity and allowing me to start a game at the major league level.”
Darren O’Day picked up his first save of the season since closer Zach Britton is on the disabled list with a forearm strain.
Britton will see a specialist Monday following a MI that came back clean.
Mancini has eight home runs this season in 17 games, which ties a major league record with Trevor Story and Carlos Delgado.
Sunday, (1-1) Kevin Gausman makes his fifth start of the season at 1:35 p.m.