put somebody on their mettle

put (one) on (one's) mettle

To put one in a situation in which they must prove their worth, skill, or ability. Being promoted to general manager at such a young age is certainly going to put her on her mettle. Our goal is to put each of these athletes on their mettle to see who earns the spot on the team.
See also: mettle, on, put
Farlex Dictionary of Idioms.

put somebody on their ˈmettle

make somebody do the best work they can, or perform as well as they can: The school inspection is going to put the teachers on their mettle.
See also: mettle, on, put, somebody
Farlex Partner Idioms Dictionary
See also:
  • cut (one) down in (one's) prime
  • cut (one) off in (one's) prime
  • cut someone off in their prime
  • prime
  • another string to (one's) bow
  • another string to your bow
  • a one-trick pony
  • one-trick pony
  • pony
  • add another string to (one's) bow