Finland's Mikko Ilonen completed a flawless 63 to claim a three-shot lead on 12 under par after the second round of the Volvo China Open.
The former British Amateur champion took advantage of the closing stretch, picking up shots at the sixth, eighth and ninth to lead Australia's Brett Rumford, who is chasing a second straight win, and Thailand's Kiradech Aphibarnrat.
Overnight leader Robert-Jan Derksen is a shot further back on 8 under par, while 12-year-old Ye Wo-cheng from China bogeyed the final two holes to card a second consecutive 79 and finish 14 over par at Binhai Lake Golf Club in Tianjin.
Ilonen's 63 equalled his lowest round on the European Tour and gives him a great chance of claiming a first victory since the second of his two wins in 2007.
"It wasn't playing as easy as it looked," the 33-year-old said. "I gave myself a lot of opportunities, especially on my back nine, and felt good with my putter.
"The score is as good as it gets, but ball-striking wise I've been better, even this year. It was a very comfortable round, I didn't put myself in trouble at all.
"I drove the ball decent, I hit more fairways than yesterday so there was no stress. It made life a bit easier.
"It's a good position to be in and it should be an interesting weekend."
Holland's Derksen produced a strong finish with three birdies in his last five holes to add a 70 to his opening 66 as he looks to end a run of 215 European Tour events without a win.
Spain's Pablo Larrazabal carded a 66 to lie two shots behind Rumford on seven under alongside England's Lee Slattery.
Meanwhile, defending champion Branden Grace - coincidentally the last man to win back-to-back events on tour in his native South Africa last year - was three under after a superb fightback.