Brendon Todd will take a one-shot lead from Byeong Hun An into the final round of a stacked WGC-FedEX St. Jude Invitational, with Rickie Fowler, Brooks Koepka and Justin Thomas in the hunt.

Scores of 64 and 65 over the first two rounds saw Todd lead the way by two shots at the halfway stage but a mixed one-under 69 on Saturday left him at 12 under for the tournament and allowed the chasing pack to close in.

Todd, who won back-to-back titles in November after a five-year trophy drought, was one under through the first nine and stayed that way after mixing three birdies with as many bogeys on the way home.

Byeong made double bogey at the par-three 11th to fall back to level par for his round but a streak of four birdies from the 13th to the 16th saw him sign for a 66 and left him just a shot back.

Fowler was flying after going out in 32, only for bogeys at the 12th and 17th to check his progress and leave him at two back on 10 under.

Heading into Sunday of the @WGCFedEx:

1. Brendon Todd (-12)
2. @ByeongHunAn (-11)
3. @RickieFowler (-10)
4. @BKoepka (-9)
5. @JustinThomas34 (-8)

Full leaderboard: https://t.co/rciogkTqs6 pic.twitter.com/w0qe4PCh2t
— PGA TOUR (@PGATOUR) August 1, 2020

Koepka toiled early in his round as a double bogey at the second and another dropped shot at six saw him fighting to remain among the leaders.

But in typical fashion, defending champion Koepka made six birdies from the ninth to the 16th hole.

A bogey at 17 derailed his momentum slightly but at three shots back Koepka is well in contention heading in Sunday.

Thomas' 66 means he is four shots back, the former world number one going four under on the back nine – including three straight birdies from the 15th to the 17th.

Phil Mickelson, Matt Fitzpatrick, Louis Oosthuizen and Chez Reavie are all five shots back.