#2 Asuka - 510 Days (NXT Women's Championship)
Asuka's NXT Women's Title reign lasted 510 days although WWE recognizes the reign as 522 days. The episode where her title reign ended aired 12-days after being filmed causing WWE to recognize her reign as 522 days. Her reign was one of the strongest booked Championship reigns of the time. She went undefeated throughout her reign not losing once in her entire NXT career.
Asuka won the NXT Women's Title at NXT TakeOver: Dallas defeating Bayley in her final match on NXT. Her win started a dominating winning streak where she went undefeated for over a whole year. No one could come close to defeating her. As a result of her dominance, WWE even had a hard time finding legitimate challengers for her.
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As a result of her never seen before dominance, she was made to relinquish her title due to an injury to her collarbone. She relinquished her title on the September 6th episode of NXT which aired on tape delay, as mentioned earlier. She would move on to the main roster ending her career in NXT during which she was entirely undefeated.