Sweden's Fredrik Jacobson took over at the top with a superb second round 66 at the World Golf Championships-HSBC Champions in Shanghai.
From two behind American Keegan Bradley overnight the 37 year old birdied four of his first seven holes and after more came at the seventh and ninth he signed for an 11 under par halfway total of 133.
Jacobson, who had his first US PGA Tour victory in America in June and was third in Malaysia last week, was two ahead of Bradley and three in front of Australian Adam Scott and South African Louis Oosthuizen.
It looked set to be another great day for US PGA Champion Bradley when he rolled in a 40 foot eagle putt on the second and a ten footer for birdie two holes later.
But the 25 year old had his first bogey of the tournament after he missed the ninth green and did well not to drop another stroke at the 456 yard 11th.
He went left again into a dip and left his chip 12 feet short, but made it to remain nine under.
Playing partner Scott, who won golf's last WGC event in Akron in August, went to the turn in a superb 31 with six birdies and a bogey.
Last year's Open Championship winner Oosthuizen was going even better, though. Also out in 31, he picked up more shots at the 12th and 13th.
England's Paul Casey was five under for the day like Scott and shared fourth place on seven under with American Bo Van Pelt, but then came a bogey six at the 14th.
That put him in a group alongside compatriot Simon Dyson and Northern Ireland's Graeme McDowell, while Lee Westwood and Rory McIlroy were still to make the move they were hoping for.
World Number Two Westwood, runner-up to Francesco Molinari last year, turned in 34, but with a bogey on the tenth was four under and World Number Three McIlroy was alongside him after three-putting the 12th.
The 22 year old US Open Champion had five birdies in the outward half, but mixed them with two bogeys.
