Haydn Porteous turned in 33 to take a one-shot lead down the back nine in the final round of the D+D REAL Czech Masters.
Lee Slattery had entered day four with a two-shot lead and while he turned in level par to stay at 12 under, that was not enough to keep the big-hitting South African at bay.
England's James Morrison was five under for his 12 holes to sit at 11 under alongside Swede Pontus Widegren who turned in 33.
Morrison made a brilliant start with birdies on the first, second and fourth to get to nine under.
Porteous almost made an eagle on the first as he spun his third inches past the hole but with Slattery only making par after finding the sand, the lead was down to one.
The 23 year old was dialled-in already and when he spun his ball back towards the target for the second hole running, he was in a share of the lead.
Morrison was putting on a clinic on the greens and when he followed a birdie on the sixth with a 20-footer on the seventh, he was just a shot off top spot.
Porteous hit a wild tee-shot on the fourth but made a birdie with his provisional to drop just a single stroke and got back into a share with the help of an excellent approach to the sixth.
Slattery had started with six straight pars as those around him jostled for position but a lovely tee-shot on the par three seventh moved him ahead on his own again.
Morrison three-putted the eighth for a first bogey of the day but bounced straight back on the ninth.
Slattery then dropped his first shot in 27 holes as he also three-putted the eighth and we were back into a tie at the top.
Widegren had been quietly going about his business with a lengthy birdie on the second and a good tee-shot to the seventh and when he holed a second monster of the day on the ninth, the Qualifying School graduate was just one behind.
That was soon two as Porteous hit an impressive approach to the ninth to get to 13 under and take the solo lead.
Tom Lewis had birdies on the first, sixth, eighth, 12th and 15th to sit ten under with three to play.
Callum Shinkwin was three under for the day through 12 holes to sit at nine under, a shot clear of Jason Scrivener and Matteo Manassero.
Lee Westwood was then the clubhouse leader at seven under.
