Updated

Ryan McIntosh, the ballperson who lost his leg when he stepped on a land mine in Afghanistan, was working the men's semifinal Sunday between Novak Djokovic and David Ferrer at the U.S. Open.

The 23-year-old McIntosh is an Army specialist. He was walking with his platoon through a river valley near Kandahar in December 2010 when he stepped on a pressure-plate land mine. He now wears a prosthetic right leg.

He learned about the chance to become a U.S. Open ballperson while competing this year at the Warrior Games, an Olympic-style sports festival for wounded soldiers.

McIntosh got good reviews early in the tournament from his supervisor and was rewarded with one of the plum assignments — a key match in Arthur Ashe Stadium on the final weekend.

Denise Castelli, an amputee who also worked last year's Open, worked Sunday's women's final.