Gay matched Fred Funk's 54-hole record from last year with a 15-under 195 through the third round. He is five ahead of second place Steve Marino, who shot a 64 Saturday.
John Merrick, the leader after the first two rounds, had a 69 Saturday that dropped him into a share of third place with Matt Kuchar (64) at 9-under 201. Esteban Toledo turned in a 63 and is in fifth at 202.
Gay will be in search of his first PGA Tour victory Sunday. He held a share of the 54-hole lead at the 2004 Colonial, finished with a 77 in the final round and tied for 14th.
"I've never had a five-shot lead, so I don't know," Gay said.