AUGUSTA, Ga. (AP) — Looking to win another green jacket, Bubba Watson surged to the Masters lead with a spree of birdies on the back side Friday.

Watson, the 2012 champion at Augusta National, sparked the best run of the tournament so far when he stuck his tee shot at No. 12 within 3 feet of the cup. He tapped in for the first of five straight birdies that pushed his second-round score to 8 under with two holes to play.

The left-hander opened with a 3-under 69 and went bogey-free through the first 26 holes, finally stumbling at the ninth. But that bogey was quickly forgotten when Watson put on a dazzling display of the golf that had the patrons roaring. He took advantage of both par 5s, sandwiched around a curling, 40-foot birdie putt at the 14th. He made it five in a row at the par-3 16th, pulling off another magnificent tee shot that rolled up about 4 feet short of the flag.

Joining David Toms, Gary Player, Geoff Ogilvy and Hale Irwin as the only players to run off nothing but birdies from the 12th to 16th holes, Watson pulled four strokes ahead of first-round leader Bill Haas, who had an afternoon tee time.

Kevin Stadler was also at 4 under and briefly in the lead until a double-bogey at the 11th knocked back the second-generation player, the son of 1982 winner Craig Stadler. They are the first father-son duo to play in the same Masters.

Thomas Bjorn had the best score in the clubhouse after birdies on four of the last five holes. He signed for a 68 that took him to 3-under 141 at the midway point.

But Louis Oosthuizen, the 2010 British Open champion who nearly won the Masters two years ago, was heading in the opposite direction.

After getting to 4 under with an eagle at the 13th, the South African ran into all sorts of problems at the other par-5 on the back side. At No. 15, his approach shot rolled back off the front of the green, plopping in the water. After a drop, Oosthuizen nearly overshot the green with his next attempt and wound up three-putting for a triple-bogey 8.

Oosthuizen lost in a playoff at the 2012 Masters, which is still remembered for Watson's improbable shot off the pine straw at the 10th hole.

Defending Masters champion Adam Scott, who opened with a 69, bogeyed the first hole and suddenly found himself six strokes off the pace.

Before Watson's run, Australia's Marc Leishman became the first player to reach 5 under when he birdied the first three holes. But he played the next seven holes at 6 over, including a double-bogey 6 on the ninth, to plummet out of contention.