Leo Cullen's side could only muster two Jonathan Sexton penalties and with a victory looming, Jackson's try sealed a win that moves Ulster closer to a fourth consecutive Guinness PRO12 play-off appearance.
There was much talk of Jackson's battle with fellow Irish outside-half Sexton, but it was the Ulster man who stole the show and he said the euphoria of such an important win definitely got the better of him.
"I still feel quite ill actually, towards the end of the game once we started pulling away I started to get so excited about the prospect of winning and I just wanted to keep fighting and fighting," the 24-year-old playmaker said.
"I was sure someone was going to catch me, but when I got about ten metres out my right calf cramped, so that's the excuse for the horrible dive at the end.
"I was a bit worried that I put the ball short, but once all the lads were jumping on top of me I knew I had got it, but I was close to being sick.
"I think it was neck and neck first-half, Sexton got two brilliant kicks either side of the pitch, so it looked like things were going to get moving and then I think towards the end of the second-half, our pack just stepped it up and made it really easy for me to get the team moving a bit - it was a good battle."
Scarlets' bonus point 34-20 win against Newport-Gwent Dragons ensured the battle for fourth place will go down to the wire and Ulster now face a high-pressure final-day trip to an Ospreys side in the hunt for a Champions Cup place.
And Jackson knows that because both teams have huge incentive to perform, it could be an epic battle at the Liberty Stadium.
"It is going to be a big game, they're fighting for top six and we're fighting for top four. Again, it is another huge game for us.
"We've had some tough games over there and I'm sure it is going to be another one."
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Guinness PRO12 Ulster News
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