最終ラウンドでチャンピオンのパンチが炸裂した. The champion's punch exploded in the final round. (研究社 新和英大辞典 第５版)
Did the punch hit really hard? Did it fail? Please explain what 炸裂 means in the Japanese sentence above, I'm not sure what "the punch exploded" means in English even and google isn't helping either.