Now O'Connell and co will travel to Clermont, who are the hot favourites for the competition, after breezing past Montpellier on Saturday.
But Munster are back in action in the RaboDirect PRO12 before that - and O'Connell believes his side can look forward to the rest of the competition with optimism.
"It means so much to these young guys, there are so many people doubting them every week, on their back every week and I know how hard they work and how much it means to them and their families," he said.
"I am sure Clermont are delighted that it is us that are coming and not Quins but I am so proud of the team.
"Guys were very low [after the loss to Glasgow], normally we rally early in the week after a poor performance but there was very little of that all week.
"I think guys were done talking almost and couldn't wait for the game to come around and I have to say up until the day before the game I wasn't sure what way it would go, even right up until kick-off.
"I am just very happy for them. It means an awful lot to the young guys I see training and working so hard. People question did they have it in them and I see it in abundance in them in training."
Guinness PRO12 Munster News
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