Replacements: Paul Jackson, Seven Sinnamon, Timothy Smith, Stuart McKenzie, Sean Conway.
Replacements: John Hogan, Podge Cleary, Eoghan Maher, Tim Quirke, Dumani Mtya.
This was ninth plays eighth and given the stakes involved, it was a real scrap throughout with Bruff taking a 10-0 half-time lead - winger Mark Cosgrave crossed for the only try.
But Dungannon eased their relegation worries, moving up to eighth in the process, with a Derek Hall touchdown and a dose of late heroics from the forwards.
Paddy Johns' charges started brightly when the Ulster-capped Ali Birch collected a Bruff kick on the Dungannon 10-metre line. The back rower's inspired run was stopped just short of the Bruff line when his offload was not collected cleanly.
But that was as good as it got for Dungannon for the next fifty minutes. The excellent Brian Cahill kept Dungannon in their own half with his trusty boot and some shrewd distribution.
In the tenth minute Bruff were awarded a penalty straight in front of the posts and Dungannon lock Michael Dunleavy received a yellow card. Cahill converted the resultant penalty for the lead score.
Four minutes later, Cahill punted a long range penalty into touch and promptly broke through after the lineout, feeding the supporting Cosgrave who dived over beside the posts for the opening try.
Cahill converted to give the Limerick club a 10-0 buffer. Cahill and McCloskey both missed with penalty attempts approaching half-time.
Out-half Cahill kept Bruff in the 'Gannon half for the most of the second period until that man Birch made a great break to lift the hosts.
Intelligently, he slowed down looking for the support which materialised in the shape of blindside flanker Hall who took Birch's offload and raced in for a try on the left after 55 minutes.
Bruff determinedly held onto their 10-5 advantage until the final 10 minutes. Dungannon then got a foothold in the Bruff 22 when McCloskey sent a penalty into touch, setting up a final push for a match-winning seven-pointer.
The Tyrone men mounted a serious and sustained assault on the Bruff try-line. With the home support in full cry, Dungannon were now intent on grabbing a late victory. A lineout, five scrums, six penalties and two sin-binnings later, referee Sean Gallagher had no option but to award Dungannon their penalty try.
With the Dungannon faithful holding their breath, McCloskey put the conversion between the posts and the four match points were in the hosts' grasp.
Although Johns will not have been best pleased with a patchy overall performance from Dungannon, they did manage to regroup well after losing the influential James McMahon in the warm-up and then seeing Dunleavy sent to the sin-bin after just 10 minutes.
This is the type of 'character building' win that could stand to the Ulster outfit as they look to improve their league position in the coming weeks - they have three league fixtures in February against Dublin University (away), Buccaneers (home) and Blackrock College (away).
Bruff will be hugely frustrated that they let this game slip from their grasp having controlled much of it. Mike Lynch's side will have an opportunity for revenge when Dungannon visit them on Saturday, March 23.
Of more pressing concern is next weekend's visit of UCD to Kilballyowen Park. They will be hoping to avenge October's disappointing 42-10 defeat at Belfield.
Referee: Sean Gallagher (IRFU)