The playoff matched five-time British Open winner Tom Watson against qualifier Don Pooley, whose last big golf moment occurred in 1987.
Watson, who earlier came back from a five-shot deficit, appeared destined to add a U.S. Senior Open title to the U.S. Open crown he won 20 years earlier.
But Pooley made a 10-foot birdie putt on the fifth playoff hole Sunday to end a battle with Watson and become the first qualifier to win the U.S. Senior Open.
More than five hours after the duo teed off at Owings Mills, Md., Pooley finally ended his 15-year winless drought
Pooley qualified for the tournament by winning a playoff, and won it the same way. The $450,000 first-place check was his biggest since his last win on the tour, the 1987 Memorial.
Watson's four-under-par 67 and Pooley's 70 left both at 10-under 274.
After they battled through 18 holes and a three-hole playoff in which the cumulative scores were totaled, they returned to the 18th hole for a sudden-death format.
Pooley made a 12-foot birdie putt, but Watson also made a birdie from the same distance. Pooley then made the winning shot on the 77th hole of the four-day tournament.
Annika Sorenstam's tuneup for next week's U.S. Women's Open was like most of her year on the LPGA Tour--perfect.
Sorenstam shot a bogey-free five-under-par 66 for a 12-under-par total of 201 and a three-stroke victory in the ShopRite LPGA Classic at Galloway Township, N.J., after Kate Golden let the lead slip away with bogeys on four of the last five holes.
The victory in the $1.2-million event was worth $180,000 and pushed Sorenstam's earnings this year to $1,534,054, more than twice the amount of the tour's No. 2 money earner, Se Ri Pak.
Colin Montgomerie might be forced to withdraw from next month's British Open because of a persistent back injury.