Dustin Johnson had a last-minute change in his bag to thank for his move to the top of the leaderboard during the second round of the WGC-HSBC Champions.
Johnson carded a birdie-free 63 to edge ahead of overnight leader Brooks Koepka, boosting his hopes of becoming the first player to win three World Golf Championship events in a calendar year.
The world No 1 experienced mixed success on the greens during an opening-round 68, but fired nine birdies on Friday after making a late switch to a different putter.
"I actually got a putter like about 20 minutes before I teed off," Johnson said after his round. "It's a Spider, so it's one that I've used before.
"I wasn't really pleased with the one I played with yesterday, so the guys here in China made me one. I got it right before I walked to the tee.
"I hit a few putts on the practice green with it and I was like, 'oh, this will work pretty well'. Went out and holed a lot of putts today, so kind of like it."
Koepka carded a blemish-free 68 and closed the gap on Johnson with back-to-back gains from the 16th, only to miss a birdie putt on the final green for a chance of a share of the halfway lead.
"I was just doing what I needed to do," Koepka said. "To be honest with you, I don't really care what Dustin is doing. If I play good, I should be fine.
"I felt like I played really good. I didn't make as many putts as yesterday, but putted really well. A couple short ones I would like to have back, but that was just green reading error."
Watch the WGC-HSBC Champions throughout the weekend live on Sky Sports Golf. Live coverage continues on Saturday from 4am.