Dustin Johnson unleashed another powerful tee shot that got lost in the darkening sky over Oakmont. Positioned some 200 yards away on a forward tee, his caddie tried to track the flight of the ball until he gave up and said, “Where did it go?”

Like he even had to ask.

One year after Johnson let the U.S. Open slip away from him at Chambers Bay, he drove his way to the top of the leaderboard Friday at Oakmont on a marathon day of 36 holes with rounds of 67-69 that left him poised for another shot at a major.

“I’ve got a good game plan for this course,” Johnson said. “And if I keep driving it like I am, I’ll be tough to beat.”

More than the long ball, Johnson has a short memory.

For all his chances in the majors — four of them and counting — he has the remarkable capacity to move on. The most crushing was last summer at Chambers Bay, when Johnson had a 12-foot eagle putt to win the U.S. Open and three-putted to finish one behind Jordan Spieth.

When asked if last year motivated him, Johnson deadpanned, “What happened last year.”

This year has been nothing short of impressive. Johnson played 27 holes before making his only bogey in two rounds. He still hasn’t made a birdie on a par 5. And he was at 4-under 136, the best score by two shots.