Ulster quashed Dragons' remote hopes of qualifying for next season's European Champions Cup as they ran out 26-22 winners at the Principality Stadium.
Due to the poor state of their Rodney Parade, Dragons have been forced to play their last three home league fixtures at the national ground.
The Welsh side needed to win them all to stand any chance of qualification but they fell at the first hurdle as Ulster fielded a near first-choice side despite them having no chance of progressing to the Pro14 final after last week's defeat to Leinster.
Stewart Moore scored two of Ulster's tries, Alby Mathewson and John Andrew the others, with Michael Lowry adding three conversions.
Ollie Griffiths, Jonah Holmes and Rio Dyer scored Dragons' tries with Sam Davies kicking a penalty and a conversion. Josh Lewis added a conversion.
Davies missed an early penalty as Dragons had the better of the opening exchanges but it was Ulster who opened the scoring in the 14th minute with an excellent try.
On a run from inside his own half, Irish international full-back Jacob Stockdale brushed aside some weak tackling to provide Mathewson with an easy run-in.
Ulster were now firmly in their stride and it came as no surprise when Moore scythed through the Dragons' defence for a second try.
Davies responded with a simple penalty before Dragons built up a head of steam. They pressurised the visitors' line with a succession of five-metre scrums and when Ulster hooker Andrew was sin-binned they looked sure to score.
However, stubborn defence from the Irish saw them keep their line intact to retain a 14-3 lead at the interval.
Three minutes after the restart, Dragons lost flanker Harri Keddie to a yellow card for a deliberate offside and when Andrew returned, he immediately finished off a driving line-out to leave the hosts with a mountain to climb.
After 50 minutes Dragons brought on Nick Tompkins, who had been released from the Wales squad, just in time to see Griffiths force his way over from close range.
The home side looked set for a comeback but a telegraphed pass from Davies was intercepted by Moore who raced 55 metres to score his second.
With 10 minutes remaining Ulster number eight Nick Timoney was sin-binned for killing the ball and spirited Dragons capitalised with tries from Dyer and Holmes to earn a deserved losing bonus point.
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