A long, late Percy Montgomery penalty ended a fraught day for the Dragons on a high note at Newport's Rodney Parade.
Dragons (7) 13
Pens: Montgomery (2)
Ulster (6) 11
Having heard earlier in the day that coach Chris Anderson would be shown the door at the end of the season, the home side trailed 11-10 on 75 minutes.
But Roger Best held onto the ball in a tackle to give Montgomery his winning penalty shot from 47m.
Jason Forster got a first-half Dragons try before a fine Bryn Cunningham score gave Ulster hope of a win.
The visitors had been allowed to play their Ireland squad members whilst the Dragons were only given Wales' Steve Jones and Luke Charteris, but both sides struggled to adapt back to league duties.
The visitors dominated possession through a turgid opening quarter, but had only a David Humphreys drop goal to show for their efforts.
The Dragons' first attack saw them gain a man advantage, as Ulster lock Matt McCullough was harshly sin-binned for lazy running when Forster's pass bounced off the retreating player.
The Gwent side failed to take advantage, though, and Humphreys' excellent tactical kicking helped set the fly-half up for a penalty to double the lead.
It looked like staying that way at the break, before Nathan Brew took a quick tap penalty with the last move of the half.
His break set up the Dragons' first multi-phased attack that ended with Steve Jones' slipped pass sending Forster under the posts for a converted try.
A Montgomery penalty early in the second period extended the lead and the Dragons looked comfortable until the final quarter.
But an Ulster break from deep in their own half led Steve Winn to make a late hit on Tyrone Howe, and a penalty to the corner left the Irish on the front foot.
Kieran Campbell prompted the visitors through a multi-phased attack that ended with Cunningham powering through opposite number Montgomery's tackle for a well-worked try in the corner.
The Dragons' attacking options looked limited as they sought to overcome the one-point deficit, but Ulster number eight Wilson held onto the ball on the floor after a heavy tackle from replacement Matthew Veater.
That gave Montgomery his penalty shot and - with the wind at his back - the Springbok star never looked like missing.
Dragons: Montgomery, Wyatt, Brew, Winn, Breeze, Warlow, Baber, Snow, Jones, Anthony, Charteris, Sidoli, Ringer, Oakley, Forster, Tuipulotu.
Replacements: Black for Tuipulotu (80). Not Used: Richards, Thomas, Veater, Trayhern, Tuipulotu, Bryant.
Ulster: Cunningham, Bowe, Steinmetz, Maggs, Howe, Humphreys, Campbell, S. Best, R. Best, Moore, Longwell, McCullough, Feather, Wilson, N. Best, Shields, Frost.
Replacements: Spee for Shields (50), S. Young for Frost (50). Not Used: Shields, McCormick, Frost, Phister, Larkin.
Referee: Andy Ireland (Scotland)