O'Mahony and co are just two points further back but travel to a Leinster side that have won their last seven RaboDirect PRO12 fixtures.
And with a European Cup quarter-final looming for both the weekend after, back row O'Mahony admits the importance of a win for either side could prove critical.
"I think there's a huge amount of pressure on both teams. I think it's a huge week for both," O'Mahony told the Irish Times.
"There's a huge amount at stake (on Saturday), but the quarter-final [of the European Cup] is the following week for both teams, so I think it's a huge primer and you want to be as good as you can be for the following week.
"They've an unbelievable quality of player. They've a great coach, they've had a great coach over the last couple of years, they believe in their game plan; everything that makes a great European team, they have. It wouldn't take a rocket scientist to know what makes them so good.
"It will take a huge collective performance, and that's when we're at our best. When we're firing as a forward pack and we're getting good ball to the backs.
"You've seen it this year probably in glimpses and some very good performances, but this is the biggest Rabo game of the year."
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Guinness PRO12 Munster News
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