Rhyss Campbell bagged Dungannon's late winner at The Showgrounds as they subjected Ballymena United to a first defeat in nine outings.
Ballymena created the first real chance of the game inside the opening ten minutes when Paul McElroy sent over a cross from the left but Shay McCartan could only send his volley wide.
At the other end Ryan Mayse had a chance from Alan Teggart's cross while Caolan McAleer found Matthew Smyth with a cross but the ball ended up being headed wide.
United's Ben Wylie was then teed up by Trai Hume although Roy Carroll dealt with the threat before making another save to deny Wylie again after half-an-hour.
After the break McAleer fired a first time effort wide from a corner before, on 79 minutes, Roy Carroll produced a world class save to deny Joshua Kelly's half volley which looked destined for the bottom corner.
Dungannon's winner arrived soon after. Another of Dungannon's new signings, Rory Patterson, delivered a free-kick into the box which Jordan Williamson could only parry to spark a goalmouth scramble before Campbell got the final touch to direct the ball home.
Ballymena United: Williamson, T. Kane, Redman, Addis, Wylie, McElroy, McCartan, Balmer, Hume, Keeley, Kelly subs Glendinning (not used), Waide (replaced Wylie 63), McGrory (replaced Kane 63), Ervin (not used), Graham (replaced Hume 86), Knowles (not used), McCready (not used)