giant killer
noun [ C ] uk/ˈdʒaɪ.ənt ˌkɪl.ər/ us/ˈdʒaɪ.ənt ˌkɪl.ɚ/
mainly UK（体育比赛中战胜了比自己强很多的对手的队伍或选手）巨人杀手
a sports player or team that defeats a much stronger opponent
Fans of FA Cup giant killers Crawley Town are celebrating their win over Derby County. 足总杯巨人杀手克罗利镇队庆祝他们打败了德比郡队。