The American enjoyed a productive day and was six under after 15 holes. However, his momentum stalled after a double-bogey on the 16th.
That put serious pressure on DeChambeau ahead of the testing 'Road Hole' and he once again struggled with a wayward tee shot.
The 28-year-old got lucky when he was granted a free drop, but the situation worsened as he then put his second shot on the tarmac.
While DeChambeau recovered to save par, the fun was not quite over as he birdied the last after another wayward tee shot.
He was once again given relief due to the proximity of the fence, and the American took full advantage.
"It is what it is," said DeChambeau, who signed for a 67 to move up to six under overall. "It's golf. It was definitely an adventurous few holes.
"I was able to get a few fortunate breaks, especially on 17 and make a beautiful par off that road.
"I hit it perfectly. It bounced up and rolled over beautifully. I was very lucky but definitely happy with the way I finished out."
The Texas golfer is on track for his best finish at the Open. Back in 2021, the player recorded his highest finish when he finished tied for 33rd.