Sergio Garcia rolled in a long birdie putt at the sixth hole in Sunday's final round of The Barclays.
Garcia entered the final round with a two shot lead but bogeyed the first hole. When Watney birdied the second, the two were tied for the lead at 9 under.
But Watney bogeyed the fifth hole to drop off the pace, and now Garcia has re-built his two-shot advantage.
Brandt Snedeker is in solo third at 7 under and 1 under for his round.
Lee Westwood and Tim Clark are both having good days and have moved into a tie for fourth. Westwood is a bogey-free 2 under on his round through 10 holes; Clark just made the turn at 2 under. Both are 6 under for the tournament.
Defending Barclays champ Dustin Johnson also is 6 under for the tournament, 3 under for his round with four holes to play.
Tiger Woods had a rollercoaster first seven holes, with three birdies and three bogeys. He has now double bogeyed the 12th hole after missing the green, then three-putting from 34 feet.
Phil Mickelson is even par through eight holes.