Masters champion Bubba Watson (71) and former PGA champion Keegan Bradley (70) were another shot back.
Johnson overcame the first threat from Snedeker with back-to-back birdies, and just like that, he was ahead by five and looked unbeatable.
His tee shot on the par-5 ninth sailed right into a patch of knee-high grass and short bushes, and Johnson never found it. Without showing any fear, he stepped up and smashed another driver dead into the wind, and then reached the green in two to salvage a two-putt bogey. He nearly drove the 12th green downwind for a birdie and a three-shot lead over Stricker, and that's when the fun began.
Johnson hit driver on the 13th and pulled it enough to land into a bunker and tumble into a native area of high grass, trees and plenty more.
"We found a shoe, some sunglasses, about five or six other balls," said Stricker, who joined in the search. "There might have been a guy living up in the tree."
Johnson found the ball, but it took two swings to get it back in play, and he had to two-putt from about 50 feet just to escape with double bogey. He thought his lead was gone as he watched Stricker, so smooth with a putter in hand, stand over his 20-foot birdie putt. It turned away at the last second.
With trouble to the right on the 14th, Johnson was predictable as ever. He pulled driver.
"He hit a couple of wayward drives and opened the door for me a little bit, and then he stepped up there with a driver again (on 14), and I'm like, 'OK.' But then he piped it, and chips it in," Stricker said with a smile. "Most guys would have been pulling out an iron or some utility club. It's amazing that he even did that, to tell you the truth."
How good can Johnson be?
"I still don't think I've lived up to my potential," Johnson said. "I played really well, but still made some mistakes. But you're always going to make some mistakes. Just limiting those will definitely help, and then for me, just making some better decisions.
"If I keep playing golf like I'm playing right now, then obviously there is no limit."