"I was thinking, 'That wasn't very good,'" he said, "'that wasn't very smart, and there goes my Open Championship.'"
Needing to play his second shot like the U.S. Open champion he was in 2010, he instead played it like a Sunday-morning hacker.
From the middle of the fairway, he duck-hooked a hybrid 150 yards straight into the trees on the left, only narrowly missing hitting a bunched gallery.
McDowell trawled through the deep rough and picked his way through the shrubs with his caddie, Ken Comboy, and the host of spotters. But the ball was lost.
So was his British Open.
McDowell hopped onto the back of a cart and was driven back up the fairway to retake the shot.
"It's the longest walk in golf, and believe me, the cart ride doesn't make it feel any shorter," McDowell said. "It was gone for me."
The Northern Irishman wound up bogeying the hole, his fourth dropped shot of the round, and fell to 3 under. It left him six shots behind playing partner Adam Scott, who was poised to win the claret jug.
McDowell had the best seat in the house as the Australian threw it all away, bogeying the last four holes in one of the biggest meltdowns in the history of major golf.
McDowell consoled Scott as the pair shook hands on the 18th green.
"It was tough to say anything
McDowell paused for breath as he described how he was feeling as Scott collapsed right in front of his eyes.
"It's hard to watch. It's hard to watch a guy do that," McDowell said. "When you hit a second shot (like his) on No. 17 and the alarm bell started to ring, I thought, 'Hold on, we've got a problem here.'"
"That putt on No. 16 which horseshoed on him was the start of a series of events that he'll think about a lot tonight."
Ernie Els won the British Open with the same score—7-under par—that McDowell started his round with. After a 75, he ended up at 2 under and tied for fifth with Luke Donald.
It was another case of what might have been, just like last month at The Olympic Club in San Francisco when he was tied for the U.S. Open lead with Jim Furyk going into the final round. He got off to a bad start that day and shot 2 over, missing out on a playoff with Webb Simpson after his birdie putt at the last hole went left of the cup.
"Going into the last round of both the U.S. Open and The Open Championship this year with chances to win, getting off to flat starts both days, I'll be analyzing why," McDowell said.
"Taking the positives away from today, you can't buy that type of education I've just had today and that education I had five weeks ago at Olympic. You just can't buy that. I'll bank those experiences and I'll move on and just know that if I keep putting myself in contention, that someday it will be my day."
Of course, McDowell doesn't have the pressure on him that the likes of Scott, Luke Donald and Lee Westwood do.
He already has a major victory in the 2010 U.S. Open at Pebble Beach. To complete a stunning year, he clinched the winning point for Europe at the Ryder Cup and then made up a four-stroke deficit against Tiger Woods in the final round of the Chevron World Challenge.
His game went through a lull in 2011, but this year has been different. He placed second to Woods in the Arnold Palmer Invitational and finished 12th at the Masters. He was third in a strong field in Abu Dhabi and runner-up to Nicolas Colsaerts at the World Match Play Championship.
McDowell is back.
"I'm not splattered on the floor right now in disappointment," he said. "I'm not beat up at all right now. I'm disappointed, yes.
"But I'm fine. I guess my disappointment kind of seems relatively stupid in relation to the guy I've just seen lose The Open Championship."
What he would do, though, to take back those early dropped shots on the second and sixth, and the trouble on No. 9 that also cost him a bogey.
And then that second shot on No. 11.
"That was just a bad pull, 15 handicapper," McDowell said. "Card-wrecker."