Dublin - Sweden's David Lingmerth fired seven birdies in a seven-under 65 on Friday to grab the halfway lead at the Memorial as five-time champion Tiger Woods scrambled to make the cut on the number.
Lingmerth's 12-under total of 132 gave him a one-shot lead over Ohio native Jason Dufner, who carded a 67 for 133.
Lingmerth ignited his round with three straight birdies at seven, eight and nine. His four birdies coming in included both of the par-threes.
"I started giving myself opportunities and the putts started dropping in," said the Swede, who is seeking a first PGA Tour title.
Dufner, a former US PGA Championship winner, had back-to-back eagles, including a hole in one at the par-three 16th - helping him bounce back from a double-bogey five at the par-three 12th.
"I'm hitting it really good," said Dufner, who showed signs of life with a tie for eighth at the Byron Nelson Championship for his first top-10 finish on US soil in a year. "I'm having enough good holes, good shots, to offset some of the mistakes I've had."
It was a further stroke back to England's Andy Sullivan, whose sparkling eight-under 64 was the low round of the day. He had eight birdies to vault into a tie for third with American Ryan Moore, who signed for a 67.
Defending champion Hideki Matsuyama, who shared the overnight lead, carded a 71 that left him sharing fifth on 135 with five other players, a group that included England's Justin Rose and Italy's Francesco Molinari.
Woods, meanwhile, had to sink a testing six-foot par putt at the 18th to secure his weekend spot in the field.
The 14-time major champion, who has fallen to 172nd in the world, started strong in his bid to rebound from a first-round 73 with three birdies in the first four holes.
But his troubles off the tee caught up with him on the back nine, where two more birdies were outnumbered by three bogeys, including late stumbles at the 16th and 17th.
He signed for a two-under par 70 for a one-under total of 143 - tied for 64th.
"I just need to put myself in position so those putts are to win tournaments, not to make cuts," he said of his par-saving effort at the last.
He had to convert a similar par putt to make the cut at the Players Championship last month.
Woods, playing his fifth tournament of a season in which he took time off to work on his game after a dismal start, said he needs to play more.
Through two rounds he has hit nine fairways, and he hit just eight greens in regulation in the second round.
Putting proved key as he made 24 putts - plus one from off a green.
"I didn't drive it very good again," said Woods, who is still working on swing changes with the US Open coming up in a fortnight.
"I feel like today I made some progress from yesterday," Woods added. "And now I need to go work on it again and I'll make some progress tomorrow. And keep doing that and hopefully it will all come together this weekend.
"And if not, two weeks from now."
Leading second-round scores on Friday in the PGA Tour $6.2 million Memorial tournament (USA unless noted, par-72):
132 - David Lingmerth (SWE) 67-65
133 - Jason Dufner 66-67
134 - Andy Sullivan (ENG) 70-64, Ryan Moore 67-67
- Hideki Matsuyama (JPN) 64-71, Jim Furyk 69-66, Francesco Molinari
(ITA) 68-67, Brendon Todd 67-68, Justin Rose (ENG) 68-67, Patrick
136 - Marc Leishman (AUS) 69-67, Bo Van Pelt 64-72
137 - Tony Finau 71-66, Erik Compton 68-69, Thomas Aiken (RSA) 69-68
- Kevin Kisner 67-71, Brendan Steele 71-67, Graham DeLaet (CAN) 69-69,
Vijay Singh (FIJ) 71-67, Andrew Putnam 72-66, Pat Perez 68-70, Chris
Stroud 70-68, Jordan Spieth 68-70, Billy Horschel 70-68, Harris English
67-71, John Huh 72-66
139 - Rory Sabbatini (RSA) 72-67, Matt
Kuchar 70-69, Troy Merritt 70-69, Jonathan Byrd 68-71, Carl Pettersson
(SWE) 72-67, Matt Jones (AUS) 71-68