Fowler, 21, ran off three straight birdies late in his round for a 6-under-par 66 to tie the 36-hole record at the Memorial Tournament and take a three-shot lead over Justin Rose into the weekend at soggy Muirfield Village in Dublin, Ohio.

Fowler was at 13-under 131, tying the tournament record set by Scott Hoch in 1987. It’s the largest 36-hole lead on the course Jack Nicklaus built since Kenny Perry led by three in 1991.

Fowler was guaranteed four rounds in the Columbus area when he arrived. No matter what happens this weekend, he has to go through 36 holes of US Open qualifying Monday, having failed to crack the top 50 in the world ranking last month.

Youth has been all the rage on the PGA Tour over the last month, with Rory McIlroy winning at Quail Hollow two days before his 21st birthday, and Jason Day winning the Byron Nelson Championship two weeks ago at age 22.

They both turned pro three years ago. Fowler didn’t turn pro until last summer, yet he already has lost in a playoff last fall and finished one shot behind in the Phoenix Open in February.

“Just being in contention the few times I have over the last eight months, this is by far the best I’ve felt,’’ Fowler said.

Defending champion Tiger Woods is starting to feel a little better, too.

Woods was just inside the projected cut line when he started, and with his lackluster play on a course that can penalize errant shots, there was some question whether he would be around for all four rounds in his final event before the US Open.

Those questions didn’t last long. He birdied three of the opening five holes, then ran off three straight birdies on his front nine to offset the few mistakes for a 69. He was at 3-under 141, 10 shots behind, but still playing.

“I hit more good shots today than I did [Thursday], and really putted well,’’ Woods said.

Phil Mickelson, who has another chance to become No. 1 with a victory, was headed in that direction with a birdie-birdie-eagle stretch on the front nine, only to give it back by missing one par putt after another on the back nine. He closed with two straight birdies for a 71 that put him at 6-under 138, still in the game but seven shots behind.

“It’s frustrating for me because I played very well and didn’t shoot the number I thought I should,’’ Mickelson said.

Jim Furyk missed a short birdie putt on the final hole and had to settle for a 67, leaving him in the group at 9-under 135 that included Tim Petrovic, who earlier in the day matched Fowler’s 66.

The second round was stopped twice by storms and rain for a total of one hour. Because of more bad weather in the forecast, the players will go off this morning in threesomes from both tees.

Champions — Tommy Armour III matched the course record with an 8-under 63 to take a three-stroke lead in the Principal Charity Classic in West Des Moines, Iowa.

Dan Forsman and Russ Cochran opened the event with 66s, and Bernhard Langer and Nick Price topped a group at 67. Forsman got as low as 7 under before a double bogey on 18.

European — Marcel Siem and Andrew Doht were tied for the lead at 6 under after the second round of the Wales Open in Newport, Wales.

Luke Donald had nine birdies to equal Chris Wood’s opening-round course record of 65, helping Donald (who shot 75 in the first round) make the cut.

Nationwide — B.J. Staten shot a 7-under 64 in the Prince George’s County Open in College Park, Md., and enters today at 11 under and with a one-shot lead over Pembroke’s Justin Peters, who followed his first round of 65 with a 4-under 67.