Brendan O'Brien joined the Saturday Panel on Off the Ball ahead of a big weekend for Irish rugby in the Champions Cup.
Munster are looking to join Leinster in an all Irish final in May and O'Brien thinks their clash with Racing will go down to the wire.
"I can see where all the positivity is coming from with Munster," he told Nathan. "I'm clouded in doubt as to how I see it going.
"Munster have gotten this far and there's been a lot of talk last year about maybe how they got to this point under Rassie Erasmus but their inability to develop a more expansive attacking game and it cost them.
"We saw it here against Saracens last year - they just didn't have it in their locker and we've had Rassie leaving mid-season and we've had Johann van Grann coming in who's done an excellent job but have they enough in their attacking locker to go that extra mile in the semi-final and final?
"I was looking through the stats of the four remaining semi-finalists this week - they have half the clean breaks of Leinster, they've 77 less defenders beaten than Racing and half the offloads but they have the stingiest defence. They've made the most tackles and they've got an excellent scrum.
"So, in a lot of ways, is it a different Munster from what we've seen in the past? It served them well in the past but in the recent past, in the last five years - it hasn't got them by that semi-final stage.
"And I think, kind of like Toulon the last day, they'll need a lot to go right and they might need that one moment of magic to get them over the line," he added.
