The pair started Saturday tied for fifth with Smith carding a bogey-free four-under 67 to move up to 11 under and a share of fourth.

American-born Mexican Ancer upstaged the game's big names with a six-under 65 lifting him to 13 under – he got off to a fast start when he birdied the first three holes at TPC Boston and made the turn in just 30 shots.

Bryson DeChambeau, who won last week's opening FedEx Cup play-offs tournament, vaulted into joint second place with a 63 that included a tap-in eagle at the par-5 18th.

Englishman Tyrrell Hatton (69) was also one behind after a birdie at the last, where he almost holed his wedge approach shot.

Justin Rose (70) is alongside Smith while halfway leader Webb Simpson carded a miserable 76 to drop seven strokes off the pace.

RIGHT: Abraham Ancer holds a one-stroke lead heading into the final round of the Dell Technologies Championship. PHOTO: Patrick Smith/Getty Images.

Rory McIlroy (66) and Jordan Spieth (68) are in a group sharing eighth at nine under.

Marc Leishman is next best of the Australians with a 69 leaving him at eight under while Adam Scott had a 73 to slip back to two over.

Tiger Woods carded a 68 on moving day to be seven under in a tie for 16th.

Ancer missed the cut at last week's Northern Trust but was not surprised by the turnaround.

"There's a very fine line from being right there fighting for the cut and fighting to win the tournament," he told NBC television.

DeChambeau, the FedEx Cup points leader, gave himself a chance of going back-to-back.

He was perhaps more excited at playing with Woods for the first time and outplaying his boyhood idol to the tune of five shots.

"To play as well as I did, that's something I'll never forget," he said.

This week's event is the second of four FedEx Cup play-offs events to determine the season-long champion on the PGA Tour.