"I was trying to hit it as close as I possibly could," he said.
The birdie gave him a 2-under 70 and tied him with David Lynn of England, who also had a 70. And it turned out to be no fluke. Returning to the 18th in the playoff, as the rain started coming out harder, Ernst hit a 3-iron to about 15 feet left of the flag that set up his stunning victory.
Phil Mickelson didn't get a chance to join them. He had a one-shot lead with three holes to play until making back-to-back bogeys, missing putts of 6 feet and 10 feet. His 20-foot birdie putt on the 18th narrowly missed, and Mickelson closed with a 73.
"I felt like I was in control, and I let it slip away there the last few holes, so it was disappointing," Mickelson said.
So ended a strange week at Quail Hollow. The greens were shockingly bad due to weather and agronomical issues, which led to several players dropping out. The sun never really came out all week, and the wind chill Sunday morning made it hard to believe it was the first weekend in May. It felt like February at Pebble Beach.
Turns out there was one final surprise.
Ernst was playing only his ninth PGA Tour event. The former UNLV golfer was No. 1,207 in the world ranking. He was in a car headed to Athens, Ga., to play a Web.com Tour event when he got the phone call that there was a tee time for him at Quail Hollow.
"This feeling is unbelievable right now," said Ernst.
The victory at Quail Hollow gets him into The Players Championship next week. He qualifies for two World Golf Championships, the PGA Championship, the Tournament of Champions next year at Kapalua and the Masters next April.
In Williamsburg, Va., Cristie Kerr made a short par putt on the second hole of a sudden-death playoff with Suzann Pettersen to win the Kingsmill Championship for the third time.
The victory was the 16th of Kerr's career, and her third in five career playoffs.
Kerr shot a 2-under 69, and Pettersen had a 67 to finish at 12-under 272 on the River Course.
Wells Fargo Championship
*-Derek Ernst -8
David Lynn -8
Phil Mickelson -7
Lee Westwood -6
Robert Karlsson -6
Daniel Summerhays +2
* - Won playoff