Memorial Tournament: Jason Dufner and David Lingmerth share lead after first round
|Memorial Tournament - first-round scores (US unless stated)|
|-7 J Dufner, D Lingmerth (Swe); -6 J Spieth, D Summerhays; -5 L Glover, J Thomas, S Saunders|
|Selected others: -2 P Mickelson, R Fowler; E L Donald (Eng); +1 R Fisher (Eng); +6 D Johnson|
Sweden's David Lingmerth and American Jason Dufner both carded seven-under 65s to share the lead after the opening round of the Memorial Tournament.
Lingmerth, who won the tournament in 2015 but has not had a top-10 finish on the US PGA Tour this year, shot an eagle, eight birdies and three bogeys.
But it was a disastrous day for world number one Dustin Johnson in Ohio.
The American had a triple bogey at the 16th in his 78 to be 13 strokes off the lead at Muirfield Village.
Johnson will defend his US Open title at Erin Hills in Wisconsin in two weeks' time - and the Memorial is seen as a key tournament in the build-up to the season's second major.
With world number six Jordan Spieth is one shot off the lead, 29-year-old Lingmerth remained cautious.
"Every time I've showed up here I've had good feelings about this place. I really love the greens," said the Swede.
"It's a very humbling game. I've been working hard all year and the results haven't really been there but I've been sticking with it.
"There's a lot of work ahead this week and (in) weeks to come obviously, so I'm just trying to take one shot at a time."