The New Zealander has faced some huge challenges as he approaches two years at the RDS but he insists the last-four encounter with his former side is the biggest yet.
"I do see this as our toughest test," said Schmidt, who's only taste of defeat in a Heineken Cup clash with Leinster came against Clermont in December last year.
"It will be tough in a myriad of ways. Clermont are opponents who we know very well and who I know particularly well. They're a world-class side and the game will be played in weather conditions that will be tough. We've had to travel a fair way, we were a little bit late arriving today because you have a few hiccups when you're travelling away and you get knocked out of your stride a little bit.
"We're going to have to pull ourselves together very quickly and make sure we're as formidable as we can be.
"Clermont have been playing very well. They won't change their rugby when it's working well. There's a good spirit in the Clermont team and we will probably see that tomorrow. We'll have to play our best game of the year."
The wet weather in Bordeaux looks like making things difficult for both teams and that could mean forward dominance proves even more important at the Stade Chaban-Delmas.
Clermont were clear victors in that particular battle when they saw off English Champions Saracens in the last round and Schmidt knows Leinster must compete in the setpiece to stand any chance of moving one step closer to retaining their European crown.
"I see the game being won up front, in the lineout and in the scrum," added Schmidt at Friday's captain's run press conference.
"We will need to get a very solid scrum and a very reliable and accurate lineout functioning. That will allow us to have an element of control in what we're doing. The weather also makes it that much more important.
"Clermont will be very, very difficult to beat if we can't compete well. If we can get on top in those two areas that would be great for us. Without that platform it will be very tough."