But the 24-year-old - who saw an earlier tricky effort hit the crossbar - came to the fore at the Kingspan Stadium as the replacement's 78th-minute penalty sealed a 17-15 victory.
"It's a big boost for him," said Kiss. "When you're at that level of play you can put those situations to the side and still focus on what you're paid to do.
"He delivered for us and it was nice to see him out there for sure."
The penalty sent Ulster to the top of an increasingly congested GUINNESS PRO12 table, as just five points separate the top half.
And the Irish province were made to work hard for their win - Adam Hughes and Carl Meyer tries either side of half-time had put Dragons into a 15-7 lead.
But a penalty try allied to Sean Reidy's first-half effort - both were converted - gave Jackson the platform to nail his winning kick at the death.
And while Kiss conceded it was by no means the perfect performance, the Australian says his side can learn lessons having survived to tell the tale.
"I look at what we are now, nine points from two games and on top of the ladder, we're extremely happy with that," he added. "This time of year you have to put these things together.
"My disappointment to one side, I thought the Dragons were pretty good.
"They had wonderful carry lines, we were under pressure and scrambled a lot, and they kept coming all day. We couldn't get traction and we're on the back foot all day.
"Sometimes you have to tough through that.
"We had four guys go off with a head knock, maybe not all as serious as the others.
"We're on top of the ladder and hopefully we learn a few lessons from that first half."
To buy tickets for the GUINNESS PRO12 Grand Final click here. Also follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the GUINNESS PRO12.
Guinness PRO12 Ulster News
63x46.png){kind=logo}