The boy first picked up a tennis racket on an island – Alameda, California. He learned at a resort under palm trees from a pro named Rosie (Bareis) and went to a celebrated campus, UCLA, where he was tutored by a coach named Billy (Martin). Mackenzie McDonald’s nickname, Mackie, brings to mind a legend named McEnroe. One of his coaches, Wayne Ferreira, scored wins over Sampras and Federer. And speaking of Roger, McDonald has practiced with legends named Fed and “Baby Fed” – Grigor Dimitrov.