AUGUSTA, Ga. — Matt Kuchar and Louis Oosthuizen moved to the top of a fast-shifting leaderboard at the Masters, each making three birdies over the front nine today to go one in front of Henrik Stenson and Peter Hanson.

Kuchar made a 15-foot putt on No. 9 to finish the front in 3-under 33 and move to 6 under for the tournament. Oosthuizen birdied 6, 7 and 8 to tie for the lead.

Hunter Mahan, Lee Westwood, Jason Dufner and Bubba Watson in a four-way tie at 4 under.

Fred Couples, the 52-year-old winner of the 1992 Masters, came in tied for the lead but shot 4-over par in his first five holes to fall to 1 under.

Tiger Woods shot an even-par 72 and finished at 3-over.