Thomas is looking for his third PGA Tour title of the year -19 J Thomas (ONS); -18 J Rahm (Spa); -17 L Griffin (US); -16 S Munoz (Col) Selected others: -15 M Fitzpatrick (Eng); -10 J Rose (Eng); -9 R McIlroy (NI); -7 T Hatton (Eng), P. Casey (Eng); -4 T Fleetwood (Eng); -3 T Woods (US)
Justin Thomas made two late birdies to keep his one-shot lead as he got to the last lap Zozo went to Championship in California.
The American birdied his two hole opening, but low scores from the pursuers saw Thomas drop out of the lead.
Birdies at 16 and 17 gave him a five-under-67 and slim Spaniard Jon Rahm, who shot a scintillating 63.
Matthew Fitzpatrick of England got a five-under 67 for a share of seventh but Tyrrell Hatton slumped to a 76.
Hatton had gone three shots behind Thomas in the third round, but fell out of the fight with the four-over round on a day of good scoring.
Justin Rose continued his improved form since golf started to sit in 31st place again while Rory McIlroy shot five. r 67 to close the third round with a tie for 36th place.