a hard act to follow
Someone or something so exemplary that it overshadows anything that follows. I don't know how Mel's replacement will be received by the staff. He was so admired and respected that he'll be a tough act to follow. That award-winning play will be a tough act to follow on Broadway.
hard act to follow
Also, tough act to follow. An outstanding performance or individual. For example, Lucy was a terrific group leader-hers is a hard act to follow, or Bob's record is excellent-it will be a tough act to follow. This expression, dating from about 1900, was originally used for a particularly good vaudeville act that made the next act look poor by comparison. It soon was extended to other enterprises.