A severe afternoon storm delayed the end of the round for an hour.
McGinley, runner-up to Clarke at Kennemer Golf and Country Club a year ago, eagled his second hole, the 11th, and unleashed a string of birdies from the 12th-15th. A bogey on the 8th kept him from sole possession of the lead in his bid for his first title in four years.
"It's not surprising that Gary Orr, Darren Clarke and I do well here -- we grew up on courses like this," McGinley said.
"It's wonderful to play on an old-fashioned course where it's important to hit the fairway."
Orr, who hasn't won since 2000 and was runner-up at the European Open in May, caught McGinley by shooting 30 on his back nine in his first tournament in a month.
Bradley Dredge of Wales, at 6 under before his last hole, double-bogeyed the par-4 9th, and dropped into a 10-man group two strokes off the lead.
Hometown player Robert-Jan Derksen aced the par-3 11th with a 7-iron in shooting a par 70.