Approach of one contralto after tense performance (6)
I believe the answer is:
tactic
'approach' is the definition.
(approach can mean a tactic or strategy)
'one contralto after tense performance' is the wordplay.
'one' becomes 'i' (Roman numeral).
'contralto' becomes 'c' (musical abbreviation).
'after' says to put letters next to each other.
'tense' becomes 't' (abbreviation used in many dictionaries).
'performance' becomes 'act' (act is a kind of performance).
'i'+'c'='ic'
't'+'act'='tact'
'ic' after 'tact' is 'TACTIC'.
'of' is the link.
(Other definitions for tactic that I've seen before include "Military means to an end" , "Manoeuvre, stratagem" , "Stratagem, procedure" , "Ruse, strategy" , "Action designed to achieve a specific end" .)