In a game or competition, if you describe a person or team as unbeatable, you mean that they win so often, or perform so well that they are unlikely to be beaten by anyone.
例句
The opposition was unbeatable...對手實力超群。With two more days of competition to go China is in an unbeatable position.還有兩個比賽日，中國隊的位置已經不可撼動。