O'Mahony believes a first win in Cardiff for Ireland since the last World Cup warm-ups four years ago restores some lost pride.
For all it's faults, Ireland's laboured five-point victory inflicted a first defeat on Warren Gatland's side in 21 months.
“That says a lot," insisted O'Mahony, who was skipper for the day. "It shows how good Wales have been and it’s a credit to them.
"We know how difficult it is to come and get a result.
“But today was about putting some pride back in Ireland jersey. I felt we did that.
"It's a difficult place to come and get a performance and a win like that. Joe alluded to it and from a player's point of view, it was a long week.
"Guys who got an opportunity couldn't wait to get out there and we certainly left the jersey in a better place than last week.
“Our set piece was below average last week and, again, we know the quality Wales have so we needed to be right. It was certainly a step forward.”
The Munster talisman admitted that, in the wake of the Twickenham disaster against England, it was a "rough week".
He added: "It’s never an easy task, wasn’t about the result, it was about the performance.
“It's good to get some things back on track, defensively we were good. We’ll certainly take a win in Cardiff.
Look, we spoke obviously about the set piece being under pressure last week and it was definitely an improvement, but as Joe said already, we have to back and have a look at it, go through our processes and have a look.
"Our process this week was a lot better. A week is a long time in rugby and we knew we had to put a performance in this week.
"We needed to represent the jersey in a lot better fashion that we did last week and I thought we did that today."
"We spoke certainly from a forwards’ point of view about putting a performance in and I thought across the 15 and the subs, I thought that it was a much better one".
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