Crossword Genius

As a concert piece, it can't fail (4)

Ross

I believe the answer is:

cert

I'm a little stuck... Click here to teach me more about this clue!

'it can't fail' is the definition.
The definition suggests a singular noun which matches the answer.

'as a concert piece' is the wordplay.
'CERT' is hidden in amongst the letters.
But, I am uncertain how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for cert that I've seen before include "Classification" , "Inevitable event" , "One sure to win (slang)" , "Sure thing (that could be dead!)" , "Sure thing, in short" .)

I've seen this clue in the Evening Standard.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.