The incident, which occurred in the 80th minute and culminated in a red card for the Belgium international, overshadowed the Welsh side's progression to the Wembley showpiece on Feb. 24.
Hazard has, however, revealed that he spoke with the youngster in the Chelsea dressing room at full time and insists that the issue is now over.
"The boy put his whole body onto the ball and I was just trying to kick the ball and I think I kicked the ball and not the boy," Hazard told Chelsea TV. "I apologize. The ball boy came in the changing room and we had a quick chat and I apologised and the boy apologized as well, and it is over. Sorry."