BALLYMENA United survived a scare to safely navigate safe passage into the last eight of the JJB Sports Irish Cup.
United started brightly with Jordan Baker heading over while a James Costello effort was deflected off the leg of Derriaghy 'keeper John Rosbotham.
Later in the half Rory Carson, an early substitute for Mark Surgenor, fired over the bar from outside the area.
However, the Amateur League visitors stunned the Sky Blues on the stroke of half-time after an Andrew Rosbotham cross from the right was deflected into his own net by Aaron Stewart.
Half-time substitute Ally Teggart calmed United's nerves with the equaliser on the hour when he connected with a Curtis Wood right wing cross to head home at the far post.
Spurred on by this Allan Jenkins almost fired United into the lead onto to rattle it against the crossbar before bouncing to safety.
And they did indeed move in front on 68 minutes after David Munster turned a header past Rosbotham.
Munster might have added a third soon after with another header, this time from a Carson delivery, while a later Costello effort also drifted wide.
A little gloss was put on the scoreline for United three minutes into stoppage time when Jenkins completed the scoring.
Ballymena United: Nelson, Black, Stewart, McCutcheon, Jenkins, Surgenor, Baker, Downey, Munster, Costello, Woods subs Carson (replaced Surgenor 8), Teggart (replaced Baker 46), Davidson (not used), Lowry (replaced Downey 74), Rodgers (not used)
Derriaghy CC: J. Rosbotham, Burke, Larmour, Patterson, McKinstry, McNaul, Elliott, Stewart, Baker, Scott, A. Rosbotham subs Arnott (replaced Scott 76), Orr (replaced Elliott 76), Stronge (replaced Larmour 64), McCullough (not used), Saulters (not used)
- James Costello fends off Derriaghy's Niall Burke (Picture: PressEye.com)