TROON, Scotland -- Dustin Johnson keeps distinguishing himself when golf is at its hardest.
Coming off consecutive victories at the U.S. Open at Oakmont and at Firestone's stingy South Course, Johnson was thought to contend at Troon. He at least ensured he would remain on the weekend in the 145th Open Championship when he birdied three holes coming home for a 2-under-par 69 Friday at Royal Troon.
Johnson sat on the cutline at 1 over par when he birdied holes 15-17, a stretch not known to yield sub-par scores. The 15th, a 499-yard par-4, is ranked the second-most difficult for the week, and the 17th, a par 3 stretching to 220 yards, is the fourth hardest.
"I just played the golf course like I should have," said Johnson, who is trying to become the third player in as many years to win back-to-back majors, following Rory McIlroy in 2014 and Jordan Spieth last year. "I feel like my game is still in really good shape."
Johnson, 32, who has risen to No. 2 in the world, overcame double bogeys at Nos. 7 and 11 after poor drives, which he attributed to water on the clubface.
"I know when I make a bad swing, but they were both good swings, just with the water they squirted," he said.
He hasn't made many bad swings of late. There were some yesterday, too, which led to an even-par 71 in calm conditions -- which you would've thought Johnson would've taken advantage of.
Still, sitting at 2-under 140, Johnson trails Phil Mickelson by eight strokes, so he can't afford many mistakes this weekend.
"Tomorrow I'm going to need to go out and shoot a really good score," Johnson said. "I know I'll be off pretty early in front of the leader, so just go out and post a number. I've got 36 holes to see how good I am."
As if his previous 144 holes before this week weren't indication enough.