The 29-year-old began the round with a four-shot lead and birdied the second and third before running into trouble at the par-four eighth.
"I was hitting the ball just fine all day and then I tugged a six-iron and watched it sail into the water and make a sensational splash," said Merritt, who made double-bogey.
"I felt good over the putts and I hit some good ones that didn’t go in. It was pretty stress free for the most part."
Tied for second on 11 under par were defending champion Matt Kuchar, who shot a 68, and fellow Americans Brendon Todd (63) and Kevin Kisner (67).
Kuchar, who made six birdies, was held back by a bad ricochet at the par-three seventh.
"I played some pretty good golf but got a bad break," he said. "I hit a beautiful shot in but it caught a limb and it ended up costing me a double bogey."
One more shot back were 2010 winner Jim Furyk (68), Brice Garnett (65) and Branden Grace of South Africa (66).
Masters champion Jordan Spieth stayed in the hunt, shooting a 68 for a 204 total, five shots off the pace along with Bo Van Pelt (67), despite starting the tournament with a 74.
"I came back strong and (am) glad to be here having a chance tomorrow," said the 21-year-old Texan.
Spieth said he spent some of his off time answering hundreds of messages after his Masters triumph.
"It was really nice to have so much support and to see the non-golf community is so interested in the Masters," he said, noting well wishes from NBA stars including Dirk Nowitzki and Steph Curry and former Cowboys quarterback Troy Aikman.
Seven players were tied at 205, including England's Luke Donald, Brendon de Jonge of Zimbabwe, Northern Irishman Graeme McDowell and South African Louis Oosthuizen.
Due to forecasts of bad weather, final-round play will feature threesomes from split tees from 7:30 a.m.
(Reporting by Larry Fine in New York; Editing by Gene Cherry)
Share
