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SPRINGFIELD, N.J. – While five-time major winner Phil Mickelson drove it left onto Shunpike Road to start his afternoon and first-round leader Jimmy Walker drove it left into a hospitality tent coming home to the clubhouse near evening, formerly struggling Robert Streb hit it straight and true Friday at the 98th PGA Championship, all the way to a record-tying 63 and share of the second-round lead.

A 63 now has been shot 28 times in major-championship history, and three times already in the past two weeks after Mickelson did so to start the British Open and Henrik Stenson finished with one to beat Mickelson for the Claret Jug at Troon.

Four of those 63s have come at Baltusrol Golf Club, where Jack Nicklaus and Tom Weiskopf each shot one in the 1980 U.S. Open and Thomas Bjorn did the same at the 2005 PGA.

"Happy to be part of that 63 Club, I guess," Streb said after Friday's eight-birdie, one-bogey round tied him with Walker for the lead at 9 under par heading into the weekend. Their two-day 131s tie the PGA's 36-hole scoring mark shared by seven others.

He's happy, too, to have left behind what he called the disappointment of April's Masters and June's U.S. Open during a season when he missed the cut in the first three majors and hasn't made the cut in one since a tie for 10th place at last year's PGA Championship at Whistling Straits. He won a PGA Tour event last year, but his best finish this year is a tie for 18th.

A Kansas State alumnus who spent winters playing hockey and summers golfing while he grew up in Oklahoma City, Streb won nearly $4 million in 2015 but only a little more than $665,000 so far this year now at age 29.

"Just struggled with my expectations a bit," he said. "I kind of thought it would keep going, and it has been tough. Probably learned the hard way that you've got to start over again."

He said he "found something" in his swing two weeks ago, which he used to make the cut and shoot a Saturday 66 at last week's RBC Canadian Open on his way to Baltusrol.

"It gave me a little something to chase after, I guess," he said. "I haven't played well, so my expectations are pretty low, which maybe is a good thing."

His 63 caught Walker, who followed Thursday's 65 with a Friday 66. Together, they are two shots ahead of defending PGA champion Jason Day and Argentinian Emiliano Grillo.

Stenson and two-time major winners Jordan Spieth, Martin Kaymer, Zach Johnson and one-timer Adam Scott all lurk within six shots. So, too, do Patrick Reed and Rickie Fowler, among others. Dustin Johnson, Rory McIlroy and Sergio Garcia were among the notable names who missed the cut, though.

"It's a major," Streb said. "One of those guys is going to be there. They are always there."

Walker maintained a share of his lead even after driving the ball into a tent on the 17th hole. At last year's PGA, Australian Matt Jones blasted a shot off tent carpeting, creating a snippet of video that went viral. Walker took a drop below, where spectators had trampled the grass and hay had been laid to counter Friday's rainy start.

"I didn't even go up and look at it, honestly," Walker said.

As he did Thursday, Mickelson fought his way back Friday, overcoming a triple-bogey 7 to shoot an even-par 70 that leaves him 1 over par.

"I think in the history of the PGA Championship, that's the worst start of any player's round," Mickelson said. "I'd have to look it up. I don't even know what to say. It was just a pure mental block. I striped it on the range … It was just horrific."

While Mickelson's grouping with Day and McIlroy as well as Walker's presence drew large crowds to Baltusrol's back nine late on an afternoon that had turned gorgeous, Streb finished up his 63 on No. 9 with a 21-foot putt that was as valiant as Streb's eighth-hole putt had been "pathetic."

"It was pretty noisy for the 15 people that were out there," said Streb, who said he knew he was putting for a piece of history but his caddie did not. "They obviously knew what was going on. They made a little racket when the putt went in."

Streb now joins a club that includes Tiger Woods, Gary Player, Johnny Miller, Raymond Floyd, Nick Faldo, Greg Norman, the late Payne Stewart and, yes, Nicklaus, who is honored at Baltusrol for another feat, as well.

"They didn't just put that plaque down there for no good reason," Streb said, referring to one of two plaques on the 18th hole that commemorate Nicklaus' 1967 and 1980 U.S. Open victories there.