"The wind picked up," Thorpe said. "I was just trying to hit a soft drive up there to keep it short of the bunkers. I kind of nicked it a bit, but still I thought it was in the fairway and not in the water. The bogey putt from about 20 feet kind of went down and came out. ... It's a short hole, but I think it's the toughest hole on the course."
Watson, who finished 10th during his only other appearance at the tournament in 2001, began his day with birdies on the first three holes and ended it by going 3 under on the last two. He also struggled at No. 16 before saving par.
Watson, who won the Senior British Open last weekend, put his approach shot in the bunker but made the sand save with a 15-foot putt.
"Other than the shot at 16 it was probably the best round I've played all year," he said.
His tee shot on 17 stopped 3 feet from the hole, and he sank a 19-foot putt for eagle on the final hole.
"I finished yesterday on a bad note with a bogey at 18," he said. "After making that putt for par I just said, 'Heck, let's just see if we can finish a lot stronger than we did yesterday.' ... This puts me in a good frame of mind for (Sunday)."
The last four 3M Championship winners scored in the 60s during each round. With the weather predicted to turn more favorable Sunday, Thorpe, knows a low score will be needed again.
"I said yesterday that 16, 17 under would be the winning score," Thorpe said. "I look to be right on."