England's Paul Casey, who played alongside Johnson on Sunday, matched the US Open champ's 67 but was relegated to runner-up for the second straight week. "When he gets on his game maybe he's the best ball-striker in golf, maybe the longest, and he showed it today".
Johnson opened with a bogey, needing two shots to escape greenside rough, but answered with a four-foot birdie putt at the second and closed the front nine with a seven-foot birdie putt.
All this activity was far more compelling than the actual tournament, for Johnson never looked as though he was going to lose - no matter how well Casey played.
Paired with Johnson, Casey briefly pulled within one with an eagle on the 15th, only to see Johnson make an eagle of his own to re-up the lead to three.
Johnson responded by draining a 20-footer at the next and picking up another shot at the fifth, before restoring his four-shot cushion with back-to-back birdies from the seventh.
Still in the mix was J.B. Holmes, who shot a 68 and was four shots behind.
First-round leader Roberto Castro wound up in third at 271 following a 67. Holmes finished at No. 10 in the Ryder Cup standings, one spot ahead of Fowler. US captain Davis Love III will announce three additions to his team Monday, and a fourth following the Atlanta event.
DJ blistered a wet Crooked Stick course to pick up his third win of the season - and take the lead in the FedExCup standings heading to Atlanta for the Tour Championship in two weeks.
Dustin Johnson knows as well as anyone that no matter how good he is and how well he plays, something can always go wrong in golf. Johnson answered with a pair of birdies, and he was on his way.
"I'm certainly a long shot. So I'm holding my head up very high". "But I got a chance, and golf on Sunday in fun when you have a chance".
He had a tap-in birdie at the par-five 15th and then made it a hat-trick at the 16th, before capping off his day with a 15-foot birdie at the last.
They suggested the move was precautionary, since he was out of contention anyway and still more than likely to remain in the top five on the Fedex Cup rankings for the Tour Championship in Atlanta the week after next.
Those in the top 5 can guarantee the FedExCup with a win in the Tour Championship. Bubba Watson had to settle for a 72, while Rickie Fowler shot 71 and was tied for 59th.