他的冠军地位无可争议，因为他在所有比赛中都保持了全胜战绩。

His championship status is ___unchallengeable as he remained undefeated in all matches.

他的冠军地位在连续三届卫冕后变得不可撼动。

His championship status became ___unchallengeable after defending the title for three consecutive times.