But after a Kavanagh try had allowed them to go in 8-5 up at the break, Doyle's side turned it on in the second half with tries from Gillian Bourke, Claire Molloy and Mairead Kelly.
And Doyle, who was appointed last summer, was quick to praise the two newcomers for their role in turning the tables on the Italian hosts.
"Italy away from home was always going to be a tough game to open our year," said Doyle, who also coaches at Leinster.
"They delivered on the physicality we were expecting and I'm delighted to come away with a win.
"It was great to see Niamh and Geraldine do so well - these are new players for us and they were outstanding.
"I would also give credit to the Rovigo crowd for making the day so enjoyable. There was a big crowd here and there was plenty of noise and colour."
Ireland now return home ahead of Friday's clash with France in Ashbourne and will be eager for revenge after a 19-9 defeat to Les Bleues last year.