Pablo Larrazabal shot a majestic course-record 62 to move into the outright lead after two rounds of the KLM Open on Friday.
The Spaniard came flying out of the blocks at the Kennemer Golf and Country Club with six consecutive birds after starting his round at the 10th hole.
Larrazabal picked up further shots at the second, seventh and ninth holes on his way home, a dropped shot at the eighth proving the only blotch on an otherwise flawless card.
He subsequently signed for a round of eight-under par, leaving him on 10 under for the tournament and two strokes clear of Romain Wattel and Edoardo Molinari.
The 31-year-old Larrazabal was thrilled with his round but disappointed not to be the first man to shoot a recognised sub-60 score on the European Tour.
"I was aware of the 59 more than the course record," he told the European Tour's official website. "I thought about the 59 when I started with six birdies, but the round cooled down a little bit in the middle."
Italian Molinari shot four under for the second day running and is well in contention ahead of the weekend, while Wattel's card included a run of three straight birdies between the 13th and 15th and just one dropped shot at the par-four first.
Peter Uihlein, playing alongside Wattel, almost matched Larrazabal's incredible outward 28 but shot one stroke more and three bogeys on the way home left him four shots off the pace, although the American will be happy after missing seven straight cuts earlier this season as he contended with a back injury.
He is joined on six under by Soren Hansen - who has had difficulty with a wrist complaint this year - and Richie Ramsay, whose superb five-under 65 included a hole in one at the 11th.
The only disappointment for Ramsey is that the ace did not occur four holes later, as that would have resulted in a trip to space as part of a reward from XCOR Space Expedition.
Home favourite Joost Luiten started the day as joint leader but could only shoot a level par 70, while Jamie McLeary - who only got through 16 holes on Thursday before bad light stopped play - finished his first round with a pair of bogeys and fell off the pace with a two-over 72.
Notable names to miss the cut include Jose Maria Olazabal, Thomas Bjorn and Paul Lawrie.