Spieth, the defending champion, was comfortably in first until the 12th hole, when he hit the ball into the water twice and finished with a quadruple-bogey.
Willett hits off the 12th tee on Sunday. He had five birdies and no bogeys in the final round.
Smylie Kaufman hits from the first fairway during the final round. Kaufman, playing in the Masters for the first time in his career, started the day in second place.
Jamie Donaldson climbs out of a bunker on the fourth hole Sunday.
Rory McIlroy reacts to a bunker shot on the second hole Sunday.
Spieth hits a tee shot during the third round on Saturday, April 9. Spieth shot a 1-over 73 to lead the tournament for a third straight day.
Bernhard Langer, a two-time Masters champion, was one of only five players who shot a round under par on Saturday. The 58-year-old turned back the clock with a 2-under 70, and he was two strokes off the lead at the end of the day.
Windy conditions made low scores tough to come by during this year's tournament.
Jason Day, the world's top-ranked golfer, was 1-under on Saturday. He was three strokes off the lead going into Sunday.
McIlroy had a difficult third round. The four-time major champion, playing with Spieth in the final pairing, finished with a 5-over 77.
Spieth hits a tee shot Friday, April 8, during the second round.
Tom Watson kisses his wife, Hilary, after playing the last round of his Masters career on Friday. Watson, 66, said he will no longer play in the annual event, which he won in 1977 and 1981.
McIlroy hits a shot on the fifth hole Friday. McIlroy was one of only four players who shot under par in the second round. He finished the day 3-under for the tournament, a stroke behind Spieth.
Charl Schwartzel hits out of a bunker on April 8. Schwartzel won the Masters in 2011.
Ian Poulter reacts after missing a putt on the first hole on Friday.
Danny Lee hits a drive during the second round.
Billy Horschel putts on the second green Friday.
Davis Love III plays a shot during the second round. Love, captain of the U.S. Ryder Cup team, was playing in Augusta for the first time since 2011.
Spieth hits a shot during the first round on Thursday, April 7. Spieth shot a 6-under 66 to lead the tournament by two strokes heading into Friday.
McIlroy hits a tee shot on the 11th hole Thursday. He finished the round at 2-under.
David Lingmerth hits out of a bunker on the 16th hole.
Jimmy Walker plays a sand shot on the 10th.
Zach Johnson tees off on the third hole during the first round. Johnson won the Masters in 2007.
Steven Bowditch plays his second shot on hole No. 2 on Thursday.
Rickie Fowler hits out of the trees near the first fairway.
Paul Casey tips his cap after putting on the second hole Thursday.
A scorekeeper places numbers on the leaderboard during the first round.
Spectators watch the ceremonial tee shots that were taken Thursday by legends Jack Nicklaus and Gary Player.
Arnold Palmer, center, joined Nicklaus, left, and Player on the first tee. The trio has won 13 Masters combined.
Nicklaus hits his ceremonial tee shot.