Jamieson, who played for Augusta State, won with a par on the second playoff hole after Webster made a bogey. De la Riva was eliminated on the first extra hole as the three returned to play the par-4 No. 18 until the first tournament on the 2013 Race to Dubai was decided.
Jamieson had carded an 8 under 57 in his second round at the shortened Royal Durban Golf Club course, which was adjusted to a par-65 and reduced by about 1,600 yards after being deluged on Thursday and Friday because of thunderstorms.
Jamieson’s score – the second 57 of the day after South Africa’s Jaco van Zyl – gave him a 7 under total of 123 to tie with Webster and De la Riva.
Jamieson birdied his last regular hole to snatch a place alongside Webster and De la Riva in the playoff.
AUSTRALIAN OPEN: In Sydney, Peter Senior won the Australian Open by one stroke Sunday, overcoming a three-hour delay because of gale-force winds.
The 53-year-old shot even-par 72 in the final round at The Lakes to become the oldest Australian Open champion. Senior finished with 4-under 284.
Fellow Australian Brendan Jones was second after 71, while countryman Cameron Percy finished third after 73, two strokes behind.
THAILAND GOLF CHAMPIONSHIP: In Chon Buri, Thailand, Charl Schwartzel shot 7-under 65 for the third time at the Thailand Golf Championship, wrapping up a dominating victory by 11 shots.
Schwartzel led from the first round and never slowed down, finishing with 25-under 263 at the Amata Spring Country Club for the South African’s first victory since last year’s Masters. This year’s Masters winner Bubba Watson also shot 65 to finish in a tie for second with Thai golfer Thitiphun Chuayprakong, who finished with 70.
DUBAI LADIES MASTERS: In Dubai, United Arab Emirates, Shanshan Feng of China won the Dubai Ladies Masters by five strokes on Saturday after shooting a 3-under 69 to capture her second Ladies European Tour title.
Dewi Claire Schreefel of the Netherlands (69) was next.
SHOOTOUT: In Naples, Fla., Kenny Perry and Sean O’Hair birdied five of the last six holes to win the Franklin Templeton Shootout.
The 52-year-old Perry became the oldest player to win the Shootout, and also won for the third time with a different partner.
Rory Sabbatini and Augusta native Charles Howell III made a charge on the back nine that included an eagle on a par-4 but finished one stroke back at 30-under 186. They had 15-under 57 in the scramble format in the final round on the Gold Course at Tiburon Golf Club.