"I definitely feel a little mentally stronger,'' Johnson said. "Now my focus is more or less the process and the routine of each shot rather than the outcome.''
For the second time in six weeks and the third time in four years, Johnson earned a PGA Tour victory in the Peach State when he beat Ryuji Imada to win the AT&T Classic on the first hole of a playoff Sunday.
The Iowa native closed with a 5-under 67 to match Imada (70) at 15-under 273 on the TPC Sugarloaf.
Johnson needed just one hole to finish the job against Imada. Hitting a 4-iron on his second shot, Johnson watched his ball land above the pin. He rolled in a 60-footer for eagle within 5 inches of the hole.
Imada could only offer a congratulatory handshake. His tee shot landed in the left-side rough and his 3-wood failed to clear the water in front of the green.
Laying up was not an option, Imada thought, because with Johnson in the middle of the fairway, there seemed little chance his opponent would make par.
"I knew I had to gamble even though I was in the rough,'' Imada said. "I probably could have won the tournament on 17. I only had a 6-footer up the hill, right to left. I missed it.''
Seeking to become just the third player from Japan to win on the PGA Tour, Imada lost a critical stroke with a drop that all but nullified his next approach, which landed 13 feet from the pin.
"I feel bad for him,'' Johnson said. "He'll be out here for many, many years. I think in time you'll see him on the leaderboard a lot.''
For Johnson, scoring conditions the last four days were nothing like those at Augusta National, which endured bitterly cold wind in April when Johnson matched the highest winning score in Masters history at 1-over 289.