The Dragons booked their place in the semi-finals on Friday night with a narrow 18-16 win at the John Smith's Stadium.
The French club will now face St Helens for a place in next month's Grand Final at Old Trafford.
"We believe in each other and the boys showed character and dug in very hard. I'm very proud of them. Their attitude was great. We want to keep on believing in ourselves and challenge the team that finished first," Frayssinous is quoted as saying by Sky Sports News.
"Credit to the boys - they dug in very hard. We have got a great attitude and don't want to let our teammates down. We want to be proud of wearing that jersey. It has been tough physically because we knew we would be tired but I am delighted with the win."
The Dragons play their semi-final on October 2 when they travel to St Helens.