Breathing is important. Who knew?

That handy revelation recently struck Jason Dufner, who has suddenly found a little air under his feet as he enjoys a solid stretch of golf, one void only of a victory. The 2013 US PGA champion might be on track to change that, however, after an opening seven-under 65 gave him a share of the lead in the Memorial Tournament.

Like co-leader David Lingmerth, Dufner bogeyed the 18th hole after coming up short of the green. It was the only green he missed all day on a sunny and calm afternoon at Muirfield Village Golf Club.

Dufner posted his lowest score at Muirfield Village and now must contend again with Lingmerth, who pulled away in the final two rounds to beat him in 2015.

Dufner won the most recent of his four US Tour titles at the 2016 CareerBuilder Challenge in California, but he’s had nine top-25s this season and missed only two of 14 cuts. Only three times has he finished over par.

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The key has been oxygen management.

“I’ve been working on my breathing a lot, to be honest with you,” said Dufner, referring to controlling his breathing while putting, crucial to stroking the ball with more precision and consistency. “It’s been working well all year. Some days I do it better than others. Today I was really focused on it.”

The routine is simple, he said.

“As soon as I’m doing breathing is when I go [hit the putt],” Dufner said. “As soon as when it comes out at the end is when I go. And then I have a count; one-two kind of pace I’ve been working on.”

He’s right about doing it better some days than others. In the final round of the RBC Heritage Dufner, 40, drew the ire of many viewers when he simply dropped his putter near the cup on the fifth hole after missing a short par putt. The 54-hole leader at Hilton Head, Dufner ended up with a closing 76 and fell to T-11.

Nevertheless, his improvement on the greens is significant. He ranks 47th on tour this year in strokes gained-putting. Last year he was 164th and the year before 177th.

Dufner for the third straight year broke 70 in the first round of the Memorial, but his best finish is T-19 in 2014. He’d love to change that. He is a local, after all.

“Obviously, being from the state of Ohio and having some roots here, it would be nice to win,” Dufner said.

Hey, just keep breathing.