Drona Parva 40.24

Thereafter displaying many many excellent weapons, Karna, that most honoured of all bowmen, desirous of victory pierced Subhadra's son with hundreds of shafts. Then that puissant pupil of Rama, that foremost of all men learned in the use of weapons, began to afflict Abhimanyu who was incapable of being vanquished by the foe.