Second-half goals from Declan O’Brien and David Cassidy secured a hard-fought 2-0 victory for Drogheda in their FAI Ford Cup quarter-final replay against Finn Harps as they booked a semi-final duel with rivals Dundalk.

But the Boynesiders made very hard work of it against a dogged Harps side who threatened to send this replay to extra time even after going down to 10 men in the 71st minute.

The opening goal didn’t come until five minutes after the break when O’Brien forced the ball home after a mis-hit Philip Hand shot dropped into his path.

Harps tried hard to find a way back into the tie, but it was after having Damien McNulty red-carded for a second bookable offence that they went closest to an equaliser courtesy of a Thomas McMonagle piledriver which fizzed narrowly wide.

The Drogs sealed victory two minutes into stoppage time when Cassidy walked the ball into the net as Harps were hopelessly outnumbered on the counter attack.

Drogheda quickly grabbed control in the possession stakes but struggled to break down a well-organised Harps defence and two wayward shots from David Cassidy and Peter Hynes were all the home side had to show for 20 minutes of hard graft.

Harps replied with a Tommy Bonnar shot that just cleared Micheal Schlingermann’s crossbar, but immediately there was a great chance for Drogheda when Ryan Brennan’s block on Michael Funston ricocheted straight to Declan O’Brien who angled a low drive just wide of the target with only Ciaran Gallagher to beat.

An enterprising run from Thomas McMonagle and a neat flick by Pat McCann created an opportunity for Harps veteran Kevin McHugh who failed to test Schlingermann, before David Cassidy finally registered a shot on target for Drogheda and O’Brien headed over from a measured Brennan cross.

But Schlingermann had to react smartly to tip a close-range Keith Cowan header over the bar from Funston’s deep corner kick.

Drogheda had the better chances coming up to half-time, though, and O’Brien in particular should have scored on two occasions from close-range headers.

But ‘Fabio’ came good five minutes into the second half when Harps failed to deal with Shane Grimes’ ball into the box and after Philip Hand mis-cued from point-blank range O’Brien forced the ball home from four yards.

The play became increasingly scrappy after that and Harps’ cause became that much harder on 71 minutes when right-back Damien McNulty received a second yellow card following a confrontation with Cassidy.

Hynes had an easy opportunity to put Drogheda out of sight shortly after but completely mis-cued an attempted volley after being put through on goal by Cassidy.

Ten-man Harps staged a late rally and McMonagle scraped the post with a stunning 35-yard drive, before Drogheda finally put the tie to bed in the second minute of stoppage time.

Harps were hopelessly outnumbered when an attack broke down and Cassidy played the ball to Brennan who advanced on goal before returning the ball to Cassidy who had a simple tap-in.

DROGHEDA UNITED: Micheal Schlingermann; Shane Grimes, Alan McNally, Derek Prendergast, Philip Hand; Alan Byrne (Eric Foley 74); David Cassidy, Paul O’Conor, Ryan Brennan; Peter Hynes (Graham Rusk 84), Declan O’Brien.

Subs not used: Gavin Holohan, Cathal Brady, Jason Marks, Gabriel Sava.

FINN HARPS: Gallagher; McNulty, McMonagle, Cowan, T Bonnar (Duffy 90 +2); Funston (Merritt 84), McGowan, Mailey, McCann; Forker (Paul McVeigh 72), McHugh.

Subs not used: Lee Toland, Shane McGinty, Shaun Patton, Johnny Bonnar.

Referee: Derek Tomney (Dublin).