Jason Day rolled in a 50-foot putt for one of his four birdies on the front nine Sunday as he built a three-shot lead in the PGA Championship.

For all his close calls in the majors this year, Day never had a better chance than this.

The 27-year-old Australian headed to the back nine at Whistling Straits with a nerve-settling par putt at No. 9 and a three-shot lead over Justin Rose.

Day started the final round with a two-shot lead over Jordan Spieth, and he never let the Masters and U.S. Open champion get any closer. Spieth ended his streak of 36 consecutive holes without a bogey on No. 4, and they matched birdies on the next two holes.

Spieth narrowly missed a chip for eagle on No. 6.

The final three holes set the tone for the back nine. Day holed his 50-foot birdie putt on the par-3 seventh to stretch his lead to three shots over Branden Grace, with Spieth falling four shots behind.

Day got to 19-under par with that birdie. The major championship record for score to par is 19 under, set by Tiger Woods at St. Andrews in the 2000 British Open.

Day, however, missed the eighth fairway and made bogey.

On the ninth hole, Day hammered his drive down the middle while Spieth was in the thick grass to the right. Day inexplicably chunked his shot and came up well short of the green. But he rolled in an 8-foot par putt as Spieth made bogey.

Grace opened the back nine with a double bogey behind the 10th green.

Spieth was four shots behind going to the back nine. Even if he didn't win, he still had a chance to reach No. 1 in the world with a two-way tie for second.

Along with trying to win his first major, Day was trying to avoid being the wrong kind of footnote in golf history. No one has ever had at least a share of the 54-hole lead in three straight majors without winning one of them.