Munster flanker O’Mahony came on as a second-half replacement for Caelan Doris against Italy and made a huge impact within 90 seconds.
The 31-year-old, earning his 68th cap, came up with a stunning underhand offload to set up Bundee Aki for Ireland’s sixth try.
It was a standout moment in a comfortable 50-17 victory which left Ireland on the brink of a fourth Six Nations title in seven years.
“Was it my best pass in an Ireland jersey? I’ve had a couple of good ones, but it would be top three,” O’Mahony said at a press conference.
“It’s enjoyable to be able to make a difference. I enjoyed my time on the pitch at the weekend.
“You have a battle on your hands every week. I’ve had 68 battles. I’ve worked as hard as I could to get a jersey, whether on the bench or starting. There’s nothing taken for granted.
“The back row has never been anything but the most competitive position on the pitch. We’re in a battle every week to get a jersey. I’m hugely enjoying it and learning from it.
“The performance of the starting back row on Saturday was second to none and from a team point of view you couldn’t be prouder of the way the team worked and particularly the back row. It’s a battle to get any jersey in this team.
“Do I deserve to start? I suppose you’d have to ask the coaches, it doesn’t matter what I think.”
Ireland head to Paris knowing if they manage a bonus-point win they are guaranteed to claim the title.
“I think the form has been good, we’ve been quite analytical with regard to our performance, trying to pick out what we can work on and improve on,” added O’Mahony.
“It’s a different animal going to Stade France on Saturday night and competing for a Six Nations title, we know we are going to have to be better than last Saturday.
“It’s cup final week, you don’t need any more motivation than to be winning trophies with your national team. To win in France is a different animal to lots of these games but we understand the challenges ahead.”