Clue: Chirpy redhead devastated by such a victory, perhaps (7)
Answer: PYRRHIC
Explanation: Definition: such a victory, perhaps
 **Anagram of**(… devastated) [CHIRPY + **1st letter of**(…head) "red" ].
Defn: Describing a kind of/perhaps, a victory that is won at a greater cost than is worthwhile for the victor.