The crowd at Roland Garros, the legendary home of French tennis that's now hosting Olympic boxing, erupted in applause as Nacer Zorgani's deep, resonant voice filled the venue. It wasn’t until the fourth semifinal match Thursday night — when Zorgani stood up from his seat and felt his way with a white cane — that some realized. As he and his volunteer guide, Laureline Jeunemaitre, made their way to the restroom, heads turned, and whispers filled the air.