(CNN) -- Louis Oosthuizen shot a six-under par round of 64 to claim a share of the lead at the Byron Nelson Championship on Saturday.
The South African reached the turn at one under for the day before firing five birdies on the back nine at the TPC Four Seasons Resort in Texas to jump 14 places up the leaderboard.
The round leaves the former Open champion tied with America's Brendon Todd on 10-under par with just one round to play.
Todd, who fired a 64 in Friday's second round, made more steady progress on Saturday equaling his opening round of 68.
One shot back are America's James Hahn, who shot 65, Gary Woodland (66) and Canada's Mike Weir (67).
Four players are tied for sixth on eight-under par, with Ireland's Padraig Harrington, Aussie Marc Leishman, Graham DeLaet of Canada and Morgan Hoffmann of the U.S. all well placed to challenge for the $1.242 million first prize.
Australian Greg Chalmers and America's Boo Weekley and Charles Howell III are on seven under par.
Players Championship winner Martin Kaymer is having a quieter week so far but remains in contention despite a disappointing one-over par 71.
The German, who pipped Jim Furyk at Sawgrass last weekend, finished the day in a three-way tie for 15th, five shots off the lead.