It's been a solid first-half of the season for Munster who are in the hunt at the top of the GUINNESS PRO12 table.
Nine wins from their 13 matches so far has left them third in the league, only two points behind leaders Ospreys.
But, after a 33-10 defeat to Saracens last time out, O'Mahony is making sure there are no excuses heading into the weekend's action.
"You can't hang around feeling sorry for yourself. You've got to get on with it," he told the Limerick Leader.
"We've let a huge amount of people down last weekend and we've got to dig deep and show them that it's there on Sunday, that we're better than that, that there's a performance there that they deserve and we need to show."
"I don't think we have given any excuses. We were very poor at the weekend. If guys aren't going to hold on to the ball, if guys are going to miss roles, as I said you're not going to compete with a team like Saracens.
"If you have all the money in the world, if you're Toulon or whoever, if you're going to play like that you're not going to compete.
"Munster is a team that drew in players because of what we do and I think we have to stay at it, to stick at it."
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