Belgium's Thomas Pieters has established a two-shot lead after the third round of the Czech Masters in Prague on Saturday.
The defending champion, who narrowly missed out on a medal after finishing fourth on golf's return to the Olympics in Rio last week, fired four birdies in his first 10 holes at Albatross Golf Resort before bogeying the 11th and 12th.
A two-under-par 70 took Pieters to 12 under for the week, two ahead of American Paul Peterson, who surged into contention with a best-of-the-week 64.
England's Robert Rock, meanwhile, found himself a shot further back in third after a flawless 65 that left him alongside Dane Jeff Winther on nine-under.
Matt Fitzpatrick, who currently occupies the ninth and last automatic qualification place for Europe's Ryder Cup team, remained in the top 10 with a 71, with his seven-under total enough for a share of sixth.
