The Irish province was returning to Paris for the first time since mid-October when their planned round one tie was postponed in the wake of coach Anthony Foley's sudden passing and they paid tribute with a superb display.

Tries from Simon Zebo, CJ Stander and Andrew Conway left them 25-0 ahead and in prime position to secure the win at the interval. A third quarter touch down from Niall Scannell completed the job before a late Racing consolation.

"It was tough to be back," said O'Mahony of the trip. "It was a big week for the club for many reasons and I thought it was quite a mature performance for a side for their first time being over here as a group. The performance was mature so I was happy with the lads.

"To come away to France against a side with the quality that Racing have and put in a performance like that, you have to take a huge amount of confidence from it. It's a very tough place to come and play.

"We knew that if we let them exert their game plan on us in the first 20 minutes that it would get the crowd in the game and it's tough to get back in. I think the way we started was the most pleasing thing."

The win leaves them three points ahead of second-placed Glasgow Warriors in Pool 1. The pair meet in Scotstoun next Saturday before Munster welcome Racing to Limerick and the Scots travel to Leicester in the last round.

"We've put ourselves in a decent position," said O'Mahony. "You know, as we do, that in this competition it's week by week and anything can happen. We've got to recover now, put in a big week's training and we have a massive test against an extremely good Glasgow side. A big week."