Idrissa Mandiang had the first chance for the hosts after Vitoria failed to clear but the midfielder could not get his strike on target before Anderson Carvalho hit the frame of the goal from distance.
A swift counter-attack from Boavista gave the home side the lead as Douglas Abner was put through on goal, and he calmly lofted the ball over the advancing goalkeeper.
Lica had two chances for the visitors in the second half, his first was blocked well before he blazed his second wide of the goal.
Henrique pulled Vitoria level midway through the first half after he connected well with an in-swinging corner and the defender could not clear it off the line.
Boavista goalkeeper Mika then gifted the away side the three points as Cafu hit a right-footed shot from just outside the area, and the shot stopper fluffed his lines and palmed the ball into his own goal.
The win moves Vitoria up to 12th in the Primeira Liga table, while Petit's side remain 14th. body check tags ::