"I teared up in the fairway on 18, knowing I was finally giving myself a chance," he said.
Jason Gore (67), Justin Leonard (67) and Woody Austin (69) tied for second. Jim Furyk (70) and Scott Verplank (71) were in a group of five that were two shots behind Bateman.
The greens at Warwick Hills usually draw rave reviews, but dry conditions baked the greens and frustrated the field.
"I would say they're right there with the U.S. Open in that they're really crusty and firm and bumpy around the hole," Austin said.
While Bateman's final stroke will make the highlights on TV, a putt he made at No. 17 made the win possible. He made an 8-footer, avoiding a costly bogey, after missing the green on the par-3 hole.
"My putter really bailed me out," Bateman said.
For the first time since 1999, the Buick Open winner didn't play in the final group. Third-round leader Tom Pernice Jr. shot a 75, finishing in a tie for 20th at 10 under. Jesper Parnevik, who was also in the final group, didn't fare much better with a 73 and finished tied for 16th at 11-under.
Divots: John Daly, finishing a season-best 16th, attracted the largest gallery and it included one of his famous friends, musician Kid Rock, who invited Daly to stay at his Detroit-area house during the week. ... Bateman's winning score was the highest since Singh (15 under) won his first of three Buick Opens in 1997. ... Bateman became the eighth player to win his first PGA Tour event this year and the third straight, following Angel Cabrera at the U.S. Open and Hunter Mahan at the Travelers Championship. ... The previous three first-time winners at the Buick Open were Pernice (1999), Leonard (1996) and Austin (1995). ... Leonard and Gore finished in the top 10 for the first time this year. ... Furyk was under par for the 37th straight round at Warwick Hills, dating to 1997.