If a sports player or team is ~, nobody has beaten them over a particular period of time.
She was ~ for 13 years...
= unbeaten
ADJ
If a sports player or team is ~, nobody has beaten them over a particular period of time.
She was ~ for 13 years...
= unbeaten
ADJ
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012