The Spaniard defeated Omar Jasika, Mark Philippoussis and Fernando Verdasco in the short format designed to showcase the past, present and future of the game.
Nadal was returning to action at the benefit night for his charitable foundation following two months out due to wrist problems and appendix surgery.
Fast4, dubbed tennis??? version of cricket???s Twenty20, features short sets and tie breaks in a quick-fire competition in advance of the Australian Open.
In a pair of one-set shoot-outs, Nadal thrashed 17-year-old Jasika 4-1 in just 17 minutes before requiring two minutes less to register the same score against the veteran Philippoussis.
The world No 3. then edged his compatriot Verdasco 3-2 in a best-of-five sets match, winning 2-4 4-3 4-3 3-4 4-2.