Wi shot an 8-under 64 over the Palm Course, one of two at the Walt Disney World Resort used for the final event on the tour this year.
The top 125 on the tour's money list at the end of this event will have a full exemption to play on the circuit next season.
Tommy Gainey and Camilo Villegas shared second place at 65 while those at 66 included Brian Harman, Scott Stallings and Russell Knox.
Villegas began this week ranked 150th on the money list, but if he can maintain his current position in the tournament he would wind up 107th.
The Palm Course was by far the easiest of the two layouts on Thursday. The top 12 on the leaderboard all played on that course while the best round shot on the Magnolia Course was a 68.
Wi's round was highlighted by a 15-foot eagle putt at the par-5 seventh.