Justin Rose faltered over the closing stages at the WGC-HSBC Champions for Tony Finau to take a three-shot lead into the final day.
Englishman Rose turned in 33 to open up a one-shot lead at Sheshan International Golf Club.
But Rose, who could move back to the top of the world rankings with a win, dropped three shots on the final two holes to sit three off the lead alongside American duo Patrick Reed and Xander Schauffele.
Rose found the hazard at 17 and the water at 18 for Finau to end up with the same three-shot lead that he had started the day with.
For Rory McIlroy it was another disappointing day as he followed his Friday 77 with a Saturday 75 to sit way back at eight over par in a tie for 60th.
“I’m looking forward to tomorrow,” Finau, the American Ryder Cup player, told the European Tour’s website after closing his round of 70 with three birdies.
“I’ve got a world-class field chasing after me. This is the position you want to be in and I’ll be looking to close out my first tournament in this position, which is exciting for me.
“Whether it happens or not, it’s an experience that you learn from and you continue to move forward.
“It was great to birdie the last three. It’s always a nice way to finish no matter what position you’re in.
“I didn’t have a lot going my way for the first half of the day and Rosey was making his run.
“I was just really pleased I was able to finish that way and get some momentum going into tomorrow.”
Finau boosted his hopes of a first European Tour win at just the 20th attempt with a strong finish.
The big-hitting 29-year-old from Utah picked up a shots on the par four 16th and then almost made a hole-in-one on the 17th.
The birdie was enough to see Finau regain the lead and his length off the tee allowed him to take advantage of the par five last.
While Finau completed his big finish to get to 13 under, there was trouble lurking for others.
As well as Rose’s problems, Reed found the same hazard at the 17th but got up and down to drop just a single shot.
Rose surrendered a double-bogey on the 17th and then lost another shot on the last to drop to 10 under.
Reigning Race to Dubai champion Tommy Fleetwood is five shots off the lead alongside American Andrew Putnam.
Fleetwood had been one off the lead after birdieing the third, fourth and 10th and dropping a shot on the fifth.
But he triple-bogeyed the 14th after finding the water before picking a shot back up on the last.
Putnam made one bogey in a 67 to sit a shot ahead of Thai Kiradech Aphibarnrat and fellow American Keegan Bradley, who both fired rounds of 70.
Jason Day was at six under, a shot clear of Thorbjorn Olesen, Patrick Cantlay and Billy Horschel.
Collated third round scores & totals in the World Golf Championships — HSBC Champions, Sheshan International GC, Shanghai, China Sheshan International GC, China (Gbr & Irl unless stated, Irish in bold, par 72):
203 Tony Finau 66 67 70
206 Justin Rose 69 67 70, Xander Schauffele 66 71 69, Patrick Reed 64 72 70
208 Andrew Putnam 70 71 67, Tommy Fleetwood 68 68 72
209 Keegan Bradley 69 70 70, Kiradech Aphibarnrat (Tha) 68 71 70
210 Jason Day (Aus) 71 70 69
211 Thorbjorn Olesen (Den) 75 69 67, Patrick Cantlay 70 68 73, Billy Horschel 68 72 71
212 Andrea Pavan (Ita) 72 71 69
213 Emiliano Grillo (Arg) 70 69 74, Thomas Pieters (Bel) 75 64 74
214 Haotong Li (Chn) 73 72 69, Adam Scott (Aus) 69 73 72, Alex Noren (Swe) 74 69 71, Ian Poulter 69 71 74, Cheng-Tsung Pan (Tai) 68 76 70, Rafael Cabrera-Bello (Spa) 68 73 73
215 Satoshi Kodaira (Jpn) 72 73 70, Alexander Bjork (Swe) 70 75 70, Ryan Fox (Nzl) 70 70 75, Paul Casey 73 68 74
216 Tyrrell Hatton 72 70 74, Adam Hadwin (Can) 74 68 74
217 Brooks Koepka 72 74 71, Kyle Stanley 70 69 78, Matthew Fitzpatrick 67 80 70, Alexander Levy (Fra) 71 70 76
218 Matt Wallace 69 75 74, Jon Rahm (Spa) 73 76 69, Chez Reavie 70 73 75
219 Justin Harding (Rsa) 76 71 72, Pat Perez 70 69 80, Hideki Matsuyama (Jpn) 72 70 77, Branden Grace (Rsa) 72 71 76, George Coetzee (Rsa) 69 74 76, Yechun Yuan (Chn) 78 71 70, Erik Van Rooyen (Rsa) 76 72 71, Brandt Snedeker 75 76 68, Scott Vincent (Zim) 73 73 73
220 Dustin Johnson 74 73 73, Jason Norris (Aus) 74 73 73, Sang Hyun Park (Kor) 77 71 72, Cameron Smith (Aus) 76 72 72, Yuta Ikeda (Jpn) 75 74 71, Byeong-Hun An (Kor) 75 71 74
221 Sihwan Kim (Kor) 72 74 75, Oliver Bekker (Rsa) 77 71 73, Adam Bland (Aus) 72 76 73, Patton Kizzire 74 71 76, Wen-chong Liang (Chn) 72 73 76
222 Andy Sullivan 72 71 79, Xinjun Zhang (Chn) 72 76 74, Adrian Otaegui (Spa) 72 75 75, John Catlin 75 71 76
223 Charley Hoffman 74 75 74
224 Jason Scrivener (Aus) 75 74 75, Rory McIlroy 72 77 75
225 Julian Suri 74 75 76, Brandon Stone (Rsa) 74 80 71, Ashun Wu (Chn) 73 80 72, Jorge Campillo (Spa) 73 77 75, Gaganjeet Bhullar (Ind) 72 72 81
226 Francesco Molinari (Ita) 76 75 75, Kevin Na 75 74 77
227 Brian Harman 73 73 81, Russell Knox 74 77 76
228 JC Ritchie (Rsa) 71 76 81
229 Yuki Inamori (Jpn) 74 82 73
230 Lucas Bjerregaard (Den) 77 74 79
231 Brett Rumford (Aus) 73 80 78, Yan-wei Liu (Chn) 75 79 77
