The visitors have made seven changes to their side for the match at Toronto's BMO Field as they look to maintain their unbeaten record over the hosts.
"It probably took us a day or two to reflect on our last 80 minutes, get over it and how we enjoyed battling through it and getting the 80 minutes under our belt," O'Mahony said.
"I really enjoyed captaining the side. We're focused on the 80 minutes, getting that under our belt and getting it done.
"We talked about the breakdown and, with a couple of guys going down with illness, that's not something that you can bat yourself around Tuesday and Thursday. It is up to guys to get themselves mentally right, today's a big session for us and we have to make sure we're in the right places and singing off the same hymn sheet."
Canada coach Kieran Cowley took heart from Ireland's performance during their 15-12 triumph over USA.
"We have seen a lot of these players play Heineken Cup and RaboDirect Pro12, we know them from that, but as a unit it was the first time to see them play," Crowley said.
"As a unit, they would have improved from that, it was their first hit out together and the US put them under a bit of pressure with their defence and it got a little bit messy. But I'm sure they'll improve after another week together.
"When you analyse games you take things from their game. They've had a run out now, so they will be a lot better and we have got to put in place our own things."
Ireland team: F Jones (Munster); F McFadden (Leinster), D Cave (Ulster), J Downey (Munster), A Trimble (Ulster); I Madigan (Leinster), I Boss (Leinster); T Court (Ulster), R Strauss (Leinster), M Ross (Leinster); D Tuohy (Ulster), D Toner (Leinster); K McLaughlin (Leinster), T O'Donnell (Munster), P O'Mahony (capt, Munster). Reps: S Cronin (Leinster), D Kilcoyne (Munster), D Fitzpatrick (Ulster), M McCarthy (Connacht), C Henry (Ulster), P Marshall (Ulster), P Jackson (Ulster), R Henshaw (Connacht).