The Glasgow fly-half could not disguise delight at landing the match-winning score. "As soon as I struck it I looked and saw it sailing between the posts and went off my head a wee bit," Weir said.
"I had Hoggy [Stuart Hogg] chasing after me and two seconds later I was on top of big Jim Hamilton's shoulders, celebrating. It's a bit of a blur. I'm delighted the boys dug in in the second half. We attacked with great shape and are delighted we managed to seal the win."
Stressing replacement scrum-half Cusiter's role, Weir added: "Chris delivered the perfect pass. He dropped it right over the right-hand side of my body and all I had to focus on was the drop.
"Italy had some good heat and pressure on me, but I just dropped the ball and kept my head down and thankfully my leg swung straight through. I was thinking about the routine and just getting the small coaching points right. If you get caught up in the situation one of them will fall away and that's when you'll miss. It's a difficult skill and I'm just so grateful and overwhelmed it went over."
Captain Greig Laidlaw paid tribute to the fans who had supported Scotland after the outpouring of criticism that followed from their 20-0 loss to England two weeks ago, but interim head coach Scott Johnson admitted much work remains to be done before the meeting with France in the next round of the RBS 6 Nations Championship in two weeks' time.
"The criticism last week was deserved, we didn't play well," Johnson said. "But we showed character today. On the back of a 10-2 penalty count against us in the first half, I think we showed great character. But we need to execute a little bit better more often. It's certainly better than a loss in terms of giving us a boost, but we can't get carried away with a win that could have gone the other way.
"There are things that we need to improve on, and I'm all about consistency with this team. We have to learn to win consistently, to compete consistently
"We won today. We got a little bit of luck and we showed great resolve, but it won't mean a lot if we don't put on a show against France."
Italy dominated the first 40 minutes, but Johnson rejected a suggestion that his half-time pep talk might have changed the pattern of the game.
"I didn't change much," he said. "We always talk about half-time speeches, but if it was that good I should have done it before the game. It wasn't that."