Rory McIlroy fired his third consecutive 67 to claim the outright lead after the third round of the WGC-HSBC Champions in China.
McIlroy produced his most consistent performance of the week at Sheshan International, rolling in his fifth birdie putt of the day at the last to complete a clean round and edge one ahead of Louis Oosthuizen, who birdied the first five holes in a superb 65.
Overnight leader Matt Fitzpatrick dug deep to stay in contention after an erratic day, firing a 70 to slip two shots off the lead alongside Xander Schauffele, while tournament debutant Paul Waring continued his impressive form with a 66 blighted by a bogey-six at the last.
But McIlroy will be the man to catch on the final day after he overcame a scrappy opening hole, blocking his approach way right and pitching to six feet before rattling in the par putt with playing-partners Fitzpatrick and Schauffele both lining up birdie putts from inside three feet.
McIlroy then converted a solid tee shot into the short sixth and added a third birdie at the ninth to turn in 33, and he did well to keep the errors off his card on the back nine as he birdied both the par-fives on the inward half to hit the top of the leaderboard on 15-under par.
That wrestled the clubhouse lead away from Oosthuizen, whose astonishing start hit the buffers when he ran up a bogey-six at the eighth, although he got the shot back at the 10th and added further birdies at 14 and 16 to race to 14 under.
The South African erred again at the short 17th, but he atoned with his ninth birdie of the round at the last which capped the low round of the third day and also secured his place in Sunday's final group alongside McIlroy and Schauffele.
Defending champion Schauffele also got off to a hot start with birdies at the opening three holes, but his consistency deserted him mid-round and he dropped back to 10 under par when he carded his third bogey of the day at the 11th.
But the young American staged a spirited finish as he birdied each of the final three holes to close within two of the leader along with Fitzpatrick, who mixed five birdies with three dropped shots in his 70.
Waring looked set to follow-up his Friday 65 with something even better when he birdied the first three holes, and another gain at the ninth completed an outward 32 before he took a step back with a mistake at the 11th.
But the Englishman rebounded with four birdies in five holes as he raced to 14 under, only to make a mess of the par-five last and close with a scrappy six which leaves him three behind McIlroy going into the final round of the World Golf Championship season.