Lee Westwood fired a stunning five-under-par final-round 67 to win the Ballantine's Championship and retain his status as number one in the world.
The 38-year-old Englishman ended 12 under to beat Spain's Miguel Angel Jimenez (71) by one shot.
Jimenez missed a birdie putt on 18, while South Korea's Park Sang-hyun was 10 under and Dustin Johnson nine under.
Westwood, who won in Indonesia last week, needed a top-five finish to hold off Martin Kaymer in the rankings.
Many players, including Westwood, had to finish off their third rounds, which had been curtailed by Saturday's storms, before starting round four.
Westwood resumed with a bogey on the par-three 13th, but seven birdies in 23 holes took him to 12 under.
"We had a nice bottle of red [wine] and after dinner I said 'I'll see you in the playoff tomorrow' and it nearly went that way," said Westwood, who dined with Jimenez on Saturday before winning his 21st European Tour title.
"Professional golf is all about winning and it's great to do it two weeks in a row," he added.
"When you're world number one it's always nice to come and play like you're world number one and I think I did that.
"It was nerve-wracking sitting there watching people play. You never wish ill on anyone but I'm delighted to win."
Jimenez had been leading on 10 under par after nine holes of the third round when electrical storms in the Icheon area of South Korea forced the players off the Blackstone course.
The 47-year-old completed his round on Sunday morning in level par to share the lead with Sweden's Alex Noren, who birdied three of the last five holes, and Welshman Rhys Davies who shot a four-under-par 68, to also move to 10 under par.
Davies crumbled in the final round with four bogies in his opening 10 holes before a quadruple-bogey eight on the par-four 12th completely wrecked his card and chances of winning.
Noren remained in touch and was at 10 under par at the halfway stage of the final round but successive bogeys on the 10th and 11th derailed his challenge.
Westwood, who won the Indonesian Masters to regain top spot in the world rankings, began his day with a tough chip after missing the 13th green with his last shot on Saturday.
He failed to get up and down for par but immediately made amends with a birdie on the 14th and picked up another shot on the 17th to start the final round three shots off the pace.
Two birdies on the front nine kept Westwood in touch and he sank three more on the back nine, including one on the 18th, to post the clubhouse lead on 12 under.
As Westwood sank his final birdie putt, Jimenez, on 11 under, was pushing an eight-iron approach to the par-five 15th into a greenside bunker.
The Spaniard splashed out and holed a short putt to save par and then repeated the feat after finding sand on the 17th.
However, after hitting his ball into another bunker at the back of the par-five 18th green Jimenez could only chip out to 15 feet and he pushed his birdie putt to the right of the hole to hand victory to Westwood.
Home favourite Park leapt to third on 10 under par after draining an eagle putt on the last.
America's Johnson finished with birdies on the last two holes to take sole possession of fourth on nine under after a final-round 69.