VERONA, N.Y. --- When the final round of the Turning Stone Resort Championship began, six players near the top of the leaderboard had a chance at that elusive first PGA Tour victory.

Another near the top, Augusta native Charles Howell, was threatening to win his third career title.

In the end, rookie Dustin Johnson was the last man standing.

The long-hitting Johnson birdied the final two holes Sunday, sinking an 8-foot putt on the final hole to beat Australian Robert Allenby by one shot.

"I started off the year really well, and then I don't really know what happened," said the 24-year-old Johnson, who had two top-10s in his first four starts and then missed nine cuts and withdrew from two other events. "Me and my coach sat down about a month ago and set some goals. I practiced hard and tried to get my game back."

It's back.

Johnson shot 3-under-par 69 to finish at 9-under 279. He pocketed $1.08 million of the $6 million purse, the richest of the Fall Series. That catapulted him from 128th to 41st on the PGA money list. The top 125 at the end of the year retain full exemption for 2009.

"It's kind of hard to explain. I haven't grasped everything yet," Johnson said. "Right now, I feel pretty good. I'm obviously very, very excited. ... I'll probably have to sit down and re-evaluate my goals."

Allenby (70), seeking his fifth victory and first since 2001, had a chance to tie at 18, but his 12-foot putt for birdie stopped inches short of the hole.

Howell, the overnight co-leader, struggled with 1-over-par 73 to join a group of seven players in a tie for third at 7-under. Howell has held or shared the 54-hole lead four times in his career, most recently at the AT&T Classic in May, but has yet to win.

Evans' Vaughn Taylor (70) finished in a tie for 15th at 5-under, while former Augusta State golfer Richard Johnson (71) tied for 27th at 1-under.

Tag Ridings (79), tied with Howell for the lead at 8-under entering the day, self-destructed with three bogeys, a triple bogey and a double bogey in an eight-hole span.

Johnson made a 6-foot birdie at No. 17 to tie Allenby at 8-under, but appeared to be in trouble when his second shot on the par-5 18th bounced 37 feet past the green and into the rough. He recovered with a clutch chip and made the nerve-racking putt.