Mark Wiebe, who has been to PGA Tour qualifying school eight times, sank a 15-foot birdie putt on the first hole of a playoff to defeat former champion John Mahaffey and win the $500,000 Anheuser-Busch Golf Classic today at Kingsmill.

Wiebe, 27, shot a final-round 70 for 11-under-par 273 and won $90,000 for his first PGA Tour victory.

Mahaffey, a 37-year-old Texan who has won more than $1.7 million, made a great eight-iron second shot from a concrete cart path onto the green on the par-4 playoff hole, but lost when Wiebe rolled in his downhill birdie putt. Mahaffey shot 69 -- 273 and won $54,000.

"It's been a great day," said Wiebe, who added his thoughts as he started the playoff were, "If I lose, the worst that could happen is I'm not going to have to go to tour school next year. I either win or win more."

Tournament winners and the top 125 money winners are exempted.

Scott Simpson, who lipped out a 25-foot birdie putt on the final hole, shot 66 and tied for third at 274 with third-round leader Danny Edwards (72) and Joey Sindelar (68).

Keith Fergus was next at 71 -- 275. Former Frederick pro Donnie Hammond had his best finish of the year -- tied for seventh -- and won $14,041. Hammond shot the back nine in five-under-par 30 for 68 -- 276.

Curtis Strange, the PGA Tour's leading money winner this season, failed in his bid to surpass Tom Watson's 1980 record single-season record of $530,808 on his home course. Strange shot 72 -- 278, tied for 15th and won $7,500. His season total is $527,581.

Wiebe, of Escondido, Calif., plans to invest his winnings in a home in Denver. He and his wife of seven months, Cathy, have been living at her sister's home in Allentown, Pa. Their wedding gifts are in storage in San Diego.

"When you birdie the first hole of a sudden-death playoff," said Mahaffey, whose seven tour victories include the 1978 PGA and the 1980 Kemper at Congressional in Bethesda, "that usually takes care of things. It took care of me."

Wiebe broke away from a six-way tie by birdieing four of his first five holes on the back nine.

He led Mahaffey by one shot heading to the dogleg par-4 18th, but he hit his drive through the fairway and into high rough beyond.

"I must have had some massive adrenaline going," said the stocky, red-haired Wiebe. "That was the longest drive I've hit in five years."

His long-iron second shot went onto the three-tiered green, 60 feet from the hole. He left his first putt 15 feet short, and slid just past the hole on his par putt. After Mahaffey made par, they headed for the playoff.

"My first thought was I hit a good (second) putt on 18," said Wiebe, "and missed it. So hit another good one here and you can make up for it." He did.

Tony DeLuca of Vienna shot 72 -- 215 and earned $1,035.