After opening the scoring with a penalty try, Saints added two more in the first half through Lee Dickson and Hartley himself.
Despite that start Saints found themselves five points down late in the second half after a Wasps fight back. However when a penalty 90 seconds from the final whistle was kicked deep into home territory it set up the position from which Christian Day crashed over for the tying try.
Stephen Myler's conversion brought delight on the pitch and in the stands alike, and Aviva man of the match Hartley said that the team had done what it needed to do to overcome a Wasps outfit who had not been beaten on home turf in the Aviva Premiership up to that point.
"It was a good day at the office," he told SaintsTV. "It wasn't free-flowing rugby but the purist would have loved it; there were a few good mauls in there, and from our point of view it was a great performance from the forwards. We weren't complicated. We found something that worked and it won us the game.
"In the last 15 minutes we kept going for the corner and coming up short, and you could sense the frustration in the team. But you hang in there and stick at it, and ultimately that belief won us the game.
"We do like to throw it around when we can, but when we turned up today it was heaving down with snow and we knew what we needed to do. The game plan worked and we got a five pointer."
Hartley took his team back out on the field to thank the vocal and vociferous travelling Saints supporters, adding that their backing brought the best out of the team.
"The support was immense," he said. "We always have a good travelling support and I'd like to thank them for that and ask them to keep it going in another big game next week."