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.
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.