Huddersfield moved clear of bottom-placed Leeds Rhinos with a shock 22-12 success over a side who came seeking an 11th straight win.
Giants have struggled all year and endured a bitterly disappointing Challenge Cup exit at home to Wakefield last week.
But Kelly said: “I’m just really pleased for the players after the disappointment of last Thursday.
“We talked about taking responsibility, being honest, trusting each other again and all that came to the fore
“(Assistant) Chris Thorman worked really hard on game structure and some technical things and they followed it to the tee.
“That culminated in what I thought was a great win.
“The younger players stood up and some senior players did some long stints like Michael Lawrence who did a full 80.
“As for if it was redemption, it’s a longer road than that.
“I think we need to do it again next week and back up as we’ve not done that all year,” added Kelly.
Jake Connor, who is bound for Hull FC in 2017, excelled after switching to full-back.
Kelly said: “He was outstanding.
“He’s a very talented player. It’s just disappointing further down the line we might not have his services.
“Dealing with him tonight he stepped in at full-back and showed all his credentials and capabilities.”
Hull coach Lee Radford said: “We’re really disappointed with the result.
“We’ve no qualms with it – we 100 per cent got what we deserved.
“In those conditions, in the second half, we got schooled in how to play wet weather football,” he said.
“What concerns me is this is Grand Final weather (rain) so if we show no patience in these conditions, like we did tonight, these are the conversations we’ll be having in October.”
Beforehand, Radford had said Connor did not need to impress now he had signed.
“But he did, didn’t he?” he said, the 21-year-old earning man-of-the-match.
“He’s going to be a great Hull FC player; he’s showing already he doesn’t listen to the coach! He’s on board.”