The 28-year-old Sierra Leone and on-loan Sporting Kansas City striker came off the bench just before the hour mark and went on to score the equalizing goal with a little more than five minutes left to play, before Holt bagged the winning goal deep into stoppage time.
"[His goal] was a great header. I was trying to nick it to be honest and get my head on it," Holt told the club's official website. "He was lively when he came on. He's a bit of an unknown quantity, which is good for us. He brings that element of surprise and I thought he harried well."
The win, which lifts the Canaries up to 12th place in the Premier League, was Norwich's first league victory since last December, and Holt believes that it could prove to be a turning point for the rest of the season.
"We needed that slice of luck - we haven't had that in the lat few weeks," Holt said. "Every ball that's come in, the defender has headed it. You get times like that. To get goals like we have will give the lads confidence.
"We will go away on the training ground and look to get better in certain areas and look to get better and better as the weeks go on."