In torrential conditions, Ireland didn't get off to the best of starts however, going 3-0 down to an early Veronica Schiavon penalty before full-back Niamh Briggs responded to level the scores.
Ireland rode their luck and needed a last-ditch tackle from Alison Miller to stop what seemed a certain Italy try in the first half.
Briggs then kicked her side into the lead after the break and despite some late Italian pressure, Ireland held on for a nail-biting 6-3 victory to celebrate St Patrick's Day in style.
"We haven't played like that at all this season. I told them this was like a club game in Munster and we would have to dig really deep. I think we got the rub of the green on Paddy's Day," Doyle told the Irish Times.
"I didn't think the weather was going to be as bad to be honest.
"We had to change our game plan and it was very hard. We played too much rugby in the first half.
"We just played into their hands and all they had to do was wait for us to fumble. We had to switch it around in the second half.
"If that was a dry surface we would have ran that Italian team off the park. No doubt, we would have cut them up. This is their third wet Six Nations game so they're obviously used to it.
"I could see it all going wrong for us. Everything was falling into their hands but testament to our girls."