Defending champion Thomas Pieters turned in 33 to get to 13 under and open up a three-shot lead during the third round of the D+D REAL Czech Masters.
The big-hitting Belgian won his maiden European Tour title at Albatross Golf Resort 12 months ago and was making a wonderful effort of his first defence to move ahead of Jeff Winther.
Pieters followed that victory with a win in his next start and he will be aiming to repeat the trick at next week's Made in Denmark to force himself into Darren Clarke's plans for the Ryder Cup.
Paul Peterson was then at nine under as he made a charge through the field with Peter Hanson, David Howell and Robert Rock a further shot back.
Winther made the first move as he took advantage of the par five first to move to 11 under and edge ahead.
That took the Dane to four under on the opening hole for the week after a birdie on day one and an eagle on Friday.
Winther made another birdie at the fourth to go two in front but he gave the shot straight back and when Pieters put his approach on the sixth to ten feet, there was a tie at the top.
Another Pieters birdie followed on the next as he put his tee-shot on the par three to 12 feet and rolled in the putt.
Both of the leading duo then left themselves awkward chips on the eighth and while Pieters got up and down, Winther missed a short putt to drop to ten under.
Pieters had spoken this week of being less aggressive due to having more trust in his wedge play and he laid up on the par five ninth before putting his approach to six feet to make a third birdie of the day.
The 24 year old had not dropped a shot in 28 holes, with a double-bogey on the eighth on Thursday his only blemish of the week.
American Peterson had seven birdies in his first 14 holes to storm through the field while England's Rock was six under for the day after 16.
Swede Hanson and Englishman Howell were both two under for the day having just made the turn.
Laurie Canter, Ryan Evans Charlie Ford, Robert Karlsson and Brett Rumford were then all at seven under.
