GAVIN BRENNAN'S second-half winner gave Drogheda United a slight advantage ahead of next week's return game.
Drogheda's early dominance was rewarded on eight minutes when Ryan Brennan fired past James McArdle from 12 yards after a mis-hit Stephen Quigley effort rolled into his path, and just five further minutes had elapsed when Gary O'Neill laid off to Paul O'Conor, whose first-time shot flew into the bottom corner of the Portadown net.
On 25 minutes the visitors pulled a goal back with an Aaron Burns header. And with half-time imminent, Ports' captain Kevin Braniff curled a brilliant 25-yard shot in off the bar to restore parity.
The early stages of the second half were edgy, but the Drogs edged ahead on the hour mark when Ryan Brennan teed up brother Gavin, who stroked the ball home from just inside the box.
DROGHEDA UNITED – Schlingermann; Quigley, Byrne, Prendergast, Grimes; R Brennan, O'Conor, Foley; Brady (Rusk 65), O'Neill (O'Brien 70), G Brennan.
PORTADOWN – McArdle; Andrew Burns, Ramsey, Breen, Redman; Murray, Mackle (Mouncey 65), Rooney (McCafferty 65), Aaron Burns; Braniff, Twigg.
Ref – T Marshall (Irvinestown)