Rory McIlroy of Northern Island holds his lead in Shanghai Masters despite Noh Seung-yul of South Korea who charge in round two.
Noh made the biggest move by sinking nine birdies for a 63, the lowest round of the tournament so far, leaping him from 18th place to second.
The US Open champion who shot a 64 in the opening round slips to a 69 to be 11 under par in round 2.
McIlroy was overtaken when he double-bogeyed the ninth, but collected birdies at the 11th, 13th, 15th and 18th, while Noh birdied three of his last four holes to finish off the round.
The South Korean ranked 95th in the world, claimed his biggest victory to date at the Malaysian Open last year, where he become the second-youngest winner in European Tour history. He is also a former Asian Tour rookie of the year.
Anthony Kim of the United States (68) and Louis Oosthuizen of South Africa (66) were a stroke behind Noh at eight under, followed by Padraig Harrington of Ireland (70) and Hunter Mahan of the United States (72).
Mahan, who was in second place after the opening round, also had trouble on the front nine on Friday, bogeying twice and holing just one birdie.
Ian Poulter (71) and Robert Karlsson (69) are six under, and John Daly followed his opening 69 with a 70 to match Lee Westwood (70), Colin Montgomerie (69) and Masters champion Charl Schwartzel (69) at five under.