Dustin Johnson makes poor start to The Memorial with six-over 78

Dustin Johnson endured a rare day to forget as he opened The Memorial with a six-over 78 and failed to make a single birdie at Muirfield Village.

Only three players in the 119-man field returned a higher score than Johnson, who faces a huge task to avoid missing the cut as a resurgent Jason Dufner earned a share of the first-round lead with 2015 champion David Lingmerth on seven-under par.

Jordan Spieth, joint runner-up to Kevin Kisner at last week's Dean & Deluca Invitational, continued his good form with a classy 66, while Australian stars Jason Day (75) and Adam Scott (76) were among the other big names to struggle.

Lingmerth, who edged out Justin Rose at the third play-off hole two years ago, again displayed his liking for the Jack Nicklaus layout as he birdied the first and reeled off four in a row from the fifth, although further gains at 11 and 13 were offset by mistakes at the 10th and 12th.

The Swede then launched a sublime 235-yard second to eight feet at the long 15th and converted the putt for eagle, and he got to eight under with a putt from similar range at the penultimate hole before he bunkered his approach to the last and could not get up and down to save par.

Lingmerth remained in the outright lead for much of the day until his score was matched by former PGA champion Dufner, who made six birdies and a superb eagle at the long seventh, although he could not avoid a blemish on his card at the last after also finding sand with his approach.

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Spieth started at the 10th and quickly moved to three under before dropping shots at 17 and 18, but he responded with a sparkling front nine as he birdied the second and picked up four shots over his final five holes to join Daniel Summerhays on six-under par.

Justin Thomas, a double winner in Hawaii at the start of the year, birdied four of his first five holes and went on to card a 67 along with 2009 US Open champion Lucas Glover, while fan favourites Phil Mickelson and Rickie Fowler both returned two-under 70s.

But Johnson's performance was a huge surprise as the world No 1 missed good birdie opportunities over his first six holes and then took six strokes to negotiate the short 16th, where he found water from the tee and compounded the error by three-putting.

The world No 1 spurned further birdie chances from inside 10 feet at the first and third before dropping another shot at the next, and his errant putting surfaced again at the sixth as he missed twice from inside four feet and ran up an ugly double-bogey six.

World No 3 Day, who remains without a win since last year's Players Championship, bogeyed the first two holes and dropped four shots in seven holes on the back nine before salvaging some respectability with birdies at 17 and 18, where he holed out from the sand for an unlikely three.