Johnson, who took a comfortable lead when Jason Dufner triple-bogeyed 15, was assessed a two-stroke penalty for failing to replace his ball to its original position after marking before his final putt on the 18th hole.
"I'm going to focus on the positives, because I hit a really solid putt and it's a good thing I made it," Johnson said. "No harm, no foul. It was my fault."
Johnson finished with a 2-over-par 72 for a 12-under 268 total. It was his eighth PGA Tour title. Dufner finished with a 74. Dufner won the Byron Nelson Championship last week in Irving for his second victory in a four-week span. Tommy Gainey was a distant third at 7 under after a 67.
Donald regains No. 1
Donald won the biggest event on the European Tour by four strokes. The Englishman shot 4-under 68 at Wentworth to finish at 15 under. It was Donald's second victory of the year.
"There's something sweet about going 12 months and still being No. 1," Donald said. "It's an indication that I'm doing the right things."
Major for Chapman
Roger Chapman won the Senior PGA Championship, a major for the 50-and-over set, at Harbor Shores in Benton Harbor, Mich. His closing 1-over 72 was good for a two-shot victory over four rounds and it was the Englishman's first Champions Tour victory. He finished at 13-under 271. John Cook (69) was at 11 under. Hale Irwin (68) finished another stroke back.-- AP