Phil Mickelson reacts after hitting his third shot into the water on the 15th hole Thursday. (Mike Blake/Reuters)

This is not what Phil Mickelson normally says after the opening round of the Masters: “I’ve got some issues.”

Yet that was Mickelson’s state after Thursday’s opening 4-over-par 76 at Augusta National Golf Club, matching his worst first-round score in any of his 22 Masters.

“I actually played well, and I just made a lot of little mental errors,” Mickelson said. “I made a lot of little mistakes around the green.”

The three-time Masters champ may have been among a tightly bunched group of leaders if not for two holes. At the par-4 seventh, the mess started innocently enough, with his second shot at the back of the green. But he blew his chip past the pin to the fringe on the other side of the green, then ran another chip a good 10 feet past the hole. From there, he three-putted, and the triple bogey dropped him from even to 3 over.

On the back, he found disaster at the par-5 15th. His last bogey at this hole came 14 years and 46 rounds ago. But he laid up short of the water that guards the front of the green, then hit his third shot in the drink anyway. The resulting double bogey left him blank-faced and dropped him to 4 over.

“I was really off today,” he said. “It was very disappointing.”

Contending again

Since Fred Couples turned 50, he led the 2010 Masters after the first round, led the 2012 Masters at the midway point and hasn’t finished outside the top 15. So Thursday’s opening 71, which left him tied for 12th, was hardly surprising, even at 54, even in his 30th Masters.

“I love the course, and I need to keep playing like I am,” Couples said. “When that day stops, then I can be a sacrificial lamb around here and just walk around. But really, personally, I feel like I can play this course.” . . .

Bernhard Langer, the 56-year-old two-time Masters winner, was nearly as good, holing a long par-saving putt on 18 for an even-par 72. . . .

Jason Dufner, winner of the most recent major — last year’s PGA Championship at Oak Hill — suffered through a miserable back nine . After opening with nine straight pars, he made a double bogey at 10 and a bogey at 11. He came to the par-5 13th 3 over and put his third shot over the back of the green.

From there, disaster. His fourth ran past the pin and down the embankment, just short of Rae’s Creek. He then tried to hit a lob back to the pin, but the ball caught the edge of the green and rolled back down the slope into the water. He walked 20 yards back for what was his seventh shot, put that past the pin and two-putted for a quadruple-bogey 9. That provided the backbone for his first-round 80. . . .

Luke Donald, the former world No. 1 from England, played his third shot on No. 9 from the greenside bunker but left the ball in the bunker.

He then touched the sand with his club — a violation because players are not allowed to ground their club in a bunker before they play a shot from the bunker — and was assessed a two-shot penalty, leaving him with a quadruple-bogey 8 en route to 79.