Graeme Storm of England blew a five-stroke lead midway through the third round and dropped into a four-way tie at the top of the KLM Open leaderboard on Saturday.
Storm, leading since the first round, began the day with a three-stroke advantage, which he extended to five when he birdied the 12th hole in glorious conditions on the Hilversumsche course.
But consecutive bogeys at 13 and 14 and par to the end left him at 1-under 69 and tied with Spanish duo Pablo Larrazabal (64) and Gonzalo Fernandez-Castano (66), and Scotland's Scott Jamieson (66) on a 12-under total of 198.
Peter Hanson of Sweden was a stroke behind after carding 67, and three shots off the pace were Scot Richie Ramsay (64) and England's Danny Willett (66).
''I am bit disappointed the way I finished the round today but then more disappointed to three-putt 18 when going into the green with a 6-iron,'' Storm said.
''A birdie there would have put me at 13-under par but now I find myself tied for the lead. It would have been nice to just have a few shots lead but it's not to be so I am at the top with three others, and all to play for.''
Larrazabal, who followed Storm in 2008 as French Open winner, capped his bogey-free round with five birdies over his last six holes.
The Barcelona golfer needed just eight putts over his last seven holes as he seeks to win a third European Tour title and a first since denying fellow Spaniard Sergio Garcia in last year's BMW International Open in Munich.
''It was a great finish because I was 3 over par after five holes on Thursday and now I am 12 under with 18 holes to play,'' Larrazabal said. ''I have been practicing hard to get myself again in this position and hopefully I will be there on top tomorrow afternoon.''
Jamieson also enjoyed a good finish with birdies in three of his closing four holes to post a 4-under round.
''I would have taken 4-under par when I started the day,'' Jamieson said. ''It was a bit of a slow start but the three-putt for bogey on 11 was kind of a kick up the backside and then I played well from there on.''
Fernandez-Castano, who double-bogeyed the ninth hole, ended with a flourish with three birdies over his last four holes.
Hanson, who has not tasted success since qualifying for the 2010 Ryder Cup by winning the Czech Open, birdied his closing two holes.
New Ryder Cup pick Nicolas Colsaerts of Belgium birdied his last hole for a third day running in a score of 67 for an 8-under tally.
Former U.S. PGA Championship winner Martin Kaymer, the other Europe Ryder Cup player in the field, recovered from bogeys at 16 and 17 to eagle the last in a round of 68 to move to 6 under overall.
