By Larry Fine

SPRINGFIELD, New Jersey (Reuters) - Unheralded Robert Streb fired a record-equaling 63 to share a two-shot lead with Jimmy Walker after the second round of the PGA Championship on Friday, with heavyweights Jason Day and Henrik Stenson lurking nearby.

Streb, who has one PGA Tour victory, rolled in a 20-foot birdie putt on his last hole, the ninth at Baltusrol, for the 30th round of 63 ever shot in a major championship.

He joined fellow American Walker (66) at nine-under 131.

"Most of the year has been a big struggle," said 29-year old Streb, who won the McGladrey Classic two years ago but has missed nine cuts this year including the Masters, U.S. Open, British Open and The Players.

"Felt like I kind of found something with my golf swing the last two weeks. Starting hitting it kind of solid ... and obviously made a bunch of putts today."

Walker, winless this season after winning three tournaments in 2014 and two more last year, also emerged from nowhere, after finding his putting stroke, notwithstanding his sole bogey of the day on the par-five 18th.

Walker and Streb will seek to make a year of four first-time major winners, following England's Danny Willett at the Masters, U.S. Open winner Dustin Johnson and Stenson at the British Open.

"I'm sure I'll be excited, nervous," said Walker about starting the third round in the lead. "It's more like, man, this is going to be fun."

Looming large two strokes behind are defending champion Day, and 23-year-old Emiliano Grillo of Argentina, with Stenson three back at rain-softened Baltusrol.

Day came alive after an early double-bogey, roaring back with seven birdies in his next eight holes on his way to a 65, while Grillo birdied four holes on his first nine in shooting 67.

"I kind of gave myself a little bit of a kick in the bum, especially with the double bogey on seven," said Australian Day.

"It was pretty receptive out there today. I think you could be a little bit aggressive, but also play it safe on some of the holes that you needed to. If you had the putter rolling you could get a score going."

Sweden's Stenson, who fired a sensational final-round 63 to outduel Phil Mickelson at Royal Troon two weeks ago and set a British Open scoring record of 20-under, posted his second successive 67 for fifth place.

The second round began ominously when pouring rain led to a 41-minute suspension of play a little more than an hour after the first tee shots of the day.

That downpour followed an inch (2.54 cm) of rain overnight that drenched the layout and made the tricky Baltusrol greens more receptive for approach shots.

But the sun broke through and the course dried as the day wore on, setting up a flurry of good scores that set the stage for a tension-filled battle over the last 36 holes of the year's final major championship.

Eighty-six players made the cut, which fell at two-over 142.

Among players squeezing in on the number were former U.S. Open winner Justin Rose of England (70-72), former Masters champion Charl Schwartzel (73-69) and his fellow South African, four-times major winner Ernie Els (73-69).

Players just missing the cut included former world number ones Rory McIlroy of Northern Ireland (74-69) and Luke Donald of England (72-71), while U.S. Open winner Dustin Johnson (77-72) tied for 142nd in a 156-man field that included 20 teaching pros.

(Editing by Andrew Both)