Having shipped four goals against Sligo in midweek, Declan Devine’s side conceded another three and the Brandywell faithful were far from happy.
Making matters worse was the fact all three goals were of the soft variety and all of the home side’s own making.
After just eight minutes youngster Michael Barr hesitated when attempting to clear his lines and Brennan nipped in to squeeze the ball past Ger Doherty from close range.
Two minutes after the break Drogheda struck again when Derry centre-half Shane McEleney struggled with a clearance and Brennan pounced to find the top corner.
It got worse in the 55th minute when ‘steady’ Eddie McCallion received a throw-in from Barr but his pass was intercepted by Declan O’Brien and he coolly lobbed the advancing Doherty to put the game to bed.
DERRY CITY Doherty; Barr (McNamee 85), S McEleney (Curran 61), McCallion, McCaffrey; Madden, Higgins, P McEleney (Morrison 52), McLaughlin; McDaid, Patterson.
DROGHEDA UNITED: Sava; Quigley, McNally, Prendergast, McMahon; R Brennan, Foley, Cawley (Brady 74), G Brennan; O’Brien (Breen 85), Hynes (Mulvenna 68).
Referee: N. Doyle (Dublin).