It was a move straight off the training ground and it worked to a tee.
James Arlidge sent the conversion wide, and his opposite number Humphreys kicked his first penalty, three minutes later, after an offside decision.
Ulster were having the better of possession at this stage, but the hosts were defending stoutly and shunting their opponents back in the tackle.
Humphreys missed a drop goal shot from distance and the Dragons' greater physicality came the bear as the first half wore on.
They pressed down the left flank through Smith but the move petered out after a forward pass to the lurking Luke Charteris, who had another impressive day in the lineouts.
Referee Carlo Damasco was patient in his officiating of the scrum and when BJ Botha was whistled up for a binding offence, Arlidge kicked the resulting penalty for an 8-3 lead.
In a hard-hitting first half, both sides lost players through injury as Dragons captain Tom Willis went off with a calf injury and Ulster had to replace Ryan Caldwell and Bryn Cunningham.
The scoreboard remained untouched for half-time, with Humphreys dragging a penalty wide of the target and Arlidge missing two further penalty attempts.
The ongoing issues in the scrum led to yellow cards for McKenzie and Botha before the break, and defences were again on top during the opening minutes of the second half.
Humphreys missed a penalty kick from halfway - he had the distance but not the accuracy - and livewire winger Fussell made a break which should have led to a try.
He kicked clear as Ulster built some phases in the hosts' 22, making use of a fortunate bounce to jink his way deep into the Ulster half.
However, the Dragons could not spin the ball out wide to the right where they had a clear overlap. Nigel Hall's attempted pass was blocked by Andrew Trimble.
A penalty was awarded though and Arlidge made sure the Dragons came away with some points, kicking them ahead by 11-3.
A well-struck effort from Humphreys closed the gap back to five points, but the game took a major twist on 62 minutes when the Dragons engineered their second try.
Riley scorched through the first line of defence and Jason Tovey was able to ship the ball on for the fleet-footed Fussell to dive over in the left corner for an unconverted score.
The win was effectively sewn up just minutes later when the Welshmen capitalised on some loose play from Ulster on their ten-metre line.
A high, floated pass from Botha was spilled by Humphreys, who was hammered in the tackle by Dragons replacement Steve Jones, and after twice hacking the ball on, Smith gleefully dotted down for try number three.
Full-back Tovey converted to add to Ulster's misery and the Irish side's day was summed up when, in one of their final attacks, replacement flanker Thomas Anderson knocked on with the line at his mercy.
Speaking afterwards, a happy Paul Turner, whose side sit top of the table after round one, said: "We talked long and hard over the summer and today we were able to put into action things we've worked very hard on in the pre-season.
"Two of the tries were moves straight off the training park and I'm just pleased for everybody that our season has got off to this start."
|Newport Gwent Dragons Score Card|
|Ulster Rugby Score Card|