By Michael Todt
DURBAN, Jan 12 (Reuters) - Britain's Scott Jamieson capitalised on a rare bad round from 2010 British Open champion Louis Oosthuizen with a four-under-par 68 to seize a five-stroke lead in the Volvo Golf Champions on Saturday.
Second-round leader Oosthuizen's poor front nine of 40 on his way to a 74 left him in a three-way share of second at 10-under (206) with Frenchman Julien Quesne (67) and Thongchai Jaidee (73).
Triple major winner Padraig Harrington scorched back to the clubhouse in 31 over the closing nine holes and his 67 placed him joint-fifth at eight-under with Italian Francesco Molinari (68).
Jamieson, who claimed his first European Tour victory in Durban five weeks ago at the inaugural Nelson Mandela Championship, began his round in overcast conditions with a bogey at the first hole.
A birdie at the second was offset by another bogey at the par-three fourth hole but the Scot soon clicked into gear as the rain began to pour down on the par-five eighth, when a glorious iron from over 200 yards to six feet handed him an eagle.
"The eighth is definitely what got me kick started," the 29-year-old told reporters.
"I hit a great tee shot and then I was in the middle of the fairway and thought to myself that I had a good chance at birdie. I hit a great shot to five or six feet and holed it."
Jamieson later holed a chip at the par-four 11th which began a run of three consecutive birdies and although a wayward approach at the 17th cost him a shot, he recovered with a chip-and-putt birdie at the 18th to restore his five-stroke cushion.
"On 11, I was possibly looking at a bogey and managed to chip in for a birdie. So that was perhaps a little bit of a steal, but it kept up my momentum," said Jamieson.
"I didn't play as well as I did the first two days, especially yesterday from tee to green. But I managed to score well, which is the main thing. I'm delighted to be in the position I'm in."
Jamieson said capturing his first win last month will stand him in good stead when he starts his final round.
"It's obviously slightly different circumstances, but I was very grateful that I got to the playoff and then won," said the world number 100, who beat Steve Webster and Eduardo de la Riva in the rain-shortened 36-hole event.
"I gained a lot of experience and had I shot one better in the morning and not gotten to experience a playoff, then I wouldn't have learned as much.
"There's still a long way to go, so I will just stick to my game plan as best I can. We'll see if I'm here tomorrow night."
Quesne, who last year won the Andalucia Open for his first title, fired a second consecutive 67 and the Frenchman feels he is right in contention despite the poor weather.
"I've played very well this week. I knew that I could have a low score on this course. It suits my game because it is tricky," Quesne told Reuters.
"I didn't feel too bad in the conditions. I like playing with the wind, so it's good for my game. I have a low trajectory, so I can control the ball well on days like today. I feel good about my chances tomorrow."
Four-times major winner Ernie Els was 10 strokes behind Jamieson after carding a one-under 71 while compatriot Retief Goosen, a double U.S. Open champion, continued his comeback from five months out with a 70 to lie on four-under (212). (Editing by Tom Pilcher)