To re-earn or regain someone or something through a new, successful competitive effort. A noun or pronoun is used between "win" and "back." The team is hoping to win back their championship title next week.He vowed to do whatever it takes to win his ex-wife back.
win someone or something back (from someone or something)
to regain someone or something from someone or something. I hope to win the money I lost back from the other poker players. We were not able to win Sally back from the cult. We won back everything. We won back Sally.
win back
v.
To regain, through effort or contest, something or someone that one has lost or no longer has: My friend is at the casino, trying to win back what he lost last night. Her boyfriend left her, but she's sure she will win him back.