There are several antonyms for the phrase "winned back," which means to regain something or someone that was lost or taken away. The opposite could be "lost" or "surrendered," meaning giving up or losing something permanently. Other antonyms could include "failed" or "defeated," which signifies the inability to succeed or win. Another antonym could be "forfeited," meaning to lose something as a result of wrongdoing or failure to comply with rules or agreements. Lastly, "let go" could also serve as an antonym, which means to release or relinquish something voluntarily.