Bernd Schuster's men are among a host of teams tightly bunched together near the foot of La Liga, but now sit six points clear of the bottom three following a second successive away win.
Camacho was twice left unmarked to score in the space of eight first-half minutes as Malaga seized control.
The 65th-minute dismissal of Duda, who was sent off for kicking out at Rafinha, threatened to hand Celta a lifeline, but they could not find a way back into the game and are only a point ahead of Malaga as a result.
Camacho's opener came after 24 minutes. A cross from the right found its way to the far post and the 23-year-old midfielder had time and space to tap home from close range.
Abysmal marking from a free-kick allowed Camacho to grab a second on 32 minutes with a near-post header from Duda's left-wing delivery.
Duda was subsequently dismissed for a needless show of petulance, yet Malaga were able to keep Celta at bay.
