Will Zalatoris goes into the final round of the Farmers Insurance Open with a first PGA Tour win in his sights after a superb performance on day three.
Zalatoris claimed a share of the 54-hole lead with Jason Day thanks to a seven-under-par 65 at Torrey Pines.
That took him to 14 under, level with 2015 US PGA Championship winner Day, who carded a 67.
Zalatoris had started the day six strokes adrift of midway leaders Jon Rahm, Justin Thomas and Adam Schenk.
But an eagle at the par-four second gave him early momentum and five further gains followed in a blemish-free round for last season's Rookie of the Year.
That eagle featured a 338-yard tee shot as a day Zalatoris described as perhaps the best with the driver "maybe ever" put him in position to push for a maiden tour win.
Asked how much distance he has gained following a switch to a 46-inch driver, Zalatoris replied: "Twelve yards, I've clocked it up to 127 [mph clubhead speed] and have 186 ball speed so, around here, that's huge.
"Obviously you've seen what Bryson [DeChambeau] has done, you won't be seeing me at 220 [ball speed] anytime soon but definitely the added distance has really paid dividends."
Along with Day, Zalatoris still has Rahm in his rear-view mirror, a level-par 72 keeping him at 13 under, tied for third with Aaron Rai.
Rahm carded a double bogey at the 10th and lost another shot at the 12th, but he will hope his experience of winning the U.S. Open at Torrey Pines last year can help him recover on Saturday.
Thomas, meanwhile, carded a one-over 73 and has Cameron Tringale and Sungjae Im for company on 12 under.