Flanker O'Mahony has been among the stand-out performers in the Championship for Ireland, who currently sit top of the RBS 6 Nations standings.
The Munster captain has amassed 22 caps for Ireland, having made his debut in the 2012 championship, but O'Mahony believes only now has he established himself on the international stage.
"I think I am becoming more comfortable at the level," he said.
"It took me a while. I probably wasn't fit enough, probably 18 months ago, but I feel more comfortable with my game now.
"Physically I feel much better as well.
"I have had time to develop and I have been very lucky to have some great strength and conditioning guys around me as well who have taken care of me and held me together."
The clash with Italy will be Brian O'Driscoll's last outing for Ireland in Dublin and he will win his 140th international cap, eclipsing the world record of Australian scrum-half George Gregan.
"He was the first superstar of Irish rugby and always very exciting to watch," said O'Mahony.
"You wouldn't even have to go looking for him: you would see him on the TV screen so often because he was carrying so much ball, breaking lines.
"He was probably a bit raw at the time.
"Video analysis wasn't the same and defences weren't the same so he was making big, long breaks and it was very impressive to watch.
"Not much has changed, really: last weekend he was running over guys.
"He used to run around them, now he goes over the top of them."