show (one's) mettle

show (one's) mettle

To show that one has endurance and strength of character, or the necessary skills, abilities, or traits to succeed in something. Primarily heard in US. You may be the youngest lawyer in the firm, but you certainly showed your mettle in that high-profile murder case. The new CEO showed her mettle when she joined the company in 2012 and completely restructured their dying mobile phone division into the powerhouse it is today.
See also: mettle, show