Queensland Reds' Cooper was not selected for the Qantas Wallabies as the British & Irish Lions secured a 2-1 series victory this summer - Sexton starting all three Tests.
With his former Queensland mentor now at the helm of Australia in the form of Ewen McKenzie, Cooper has been brought back into the international fold.
And the 25-year-old can't wait to make up for lost time against Sexton.
"All around the ruck he's always fighting for little inches to get ahead," Cooper said of Sexton.
"That's what I love to see in opposition players. Me looking at him, being able to go up against him, it will be interesting and one I look forward to.
"You want to play against the best players and he's definitely one of them."