The Centurions have won all 16 of their games in league and cup this season, and are the sport’s only undefeated team in 2014.
Clarkson said: “Leigh are in great form and we are aware that it will not be easy by any means. They have been one of the top Championship teams for a while now and they will be ready for the game I’m sure.
“We don’t know too much about them but we will watch plenty of video in preparation to get to know how they play: we will just focus on our game plan and treat it as a normal match.”
A spot in the semi-finals is up for grabs, with Clarkson and his team-mates aiming to end a 15-year barren spell in the Challenge Cup.
Clarkson, 24, was in the crowds as a youngster in 1999, when the Rhinos defeated London Broncos 52-16 at Wembley, the last time they lifted the famous old trophy.
They have lost six finals since, including three in a row from 2010-2012.