pi ‧ èce de ré ‧ sis ‧ tance /piˌes də reziːˈstɑːns/ BrE AmE noun [singular]
[ Date: 1700-1800 ; Language: French ; Origin: 'piece of resistance' ]
the best or most important thing in a series, which comes after everything else:
The pièce de résistance was a stunning goal in the last minute of the match.