O'Gara was awarded a controversial try in the ninth-minute of injury-time - when it looked on TV replays that he might not have grounded the ball - and the Munster man converted for Ireland to come from 20-16 down to snatch victory over an impressive Italian outfit.
Reflecting on his side's display, Ireland coach Eddie O'Sullivan said: "It was the wake-up call we needed because we played a very good Italy side. It's easy to say now but they played very well and deserve a lot of credit.
"They didn't come here to make up the numbers. They came with a gameplan and executed it well. We got into a dogfight with them, which is a difficult way to beat Italy.
"We have things to work on now. It was better in some sense that we had to work hard to get the win against Italy. I would have preferred if we had played better, but I would rather find out now if we have a couple of issues to iron out.
"It's better now than at the World Cup - that's what these warm-up games are about," he added.
For photos of tonight's historic Test match at Ravenhill, please click here.