tough act to follow

a tough act to follow and a hard act to follow (so good that whatever happens next is not likely to seem as good; a performance that is not easy to equal) — труднодостижимый уровень, высокая планка; образцовое исполнение своих обязанностей; превосходное исполнение; трудный для подражания пример (речь, выступление, роль, др. деятельность так превосходно исполненные, что идущему следом будет очень трудно превзойти это)

be a tough/hard act to follow (to be so good it is not likely that anyone or anything else that comes after will be as good) — задать/поставить очень высокую планку; о том, что (почти) невозможно сделать лучше предшественника, (почти) невозможно превзойти

Example 1: Bill's speech was excellent. It was a tough act to follow, but my speech was good also.
Example 2: Lucy sang very well. That is a tough act to follow.
Example 3: Will we ever see his like again? A titan like John Paul II will always be a hard act to follow. (Times Online) — Появится ли в будущем на папском престоле личность такого же масштаба? Иоанн Павел Второй задал очень высокую планку.
Example 4: Any list of the best trilogies of all time includes The Lord of The Rings. These hugely successful films are a tough act to follow, but filmmaker Peter Jackson decided to try with The Hobbit: An Unexpected Journey.

have a tough/hard act to follow

Example: In spite of the fact that I had a tough act to follow, I did my best.

Related expressions:
hard to beat / take some beating = >
[hard to beat]
[streets ahead of sb]
[cut above sb]
[not a patch on sb]
[heads and shoulders above sth]
[run circles around sb]
[knock spots off sth]
[can't hold a candle to sb]
[give one a run for one's money] 2