Nicolas Colsaerts opened up a four-shot lead at the Turkish Airlines Open by carding a second successive seven-under 64 on Friday.
The Belgian shared the overnight lead with Haydn Porteous and Joost Luiten but was the only one of the trio to maintain their challenge in the sixth event of the lucrative Rolex Series.
Colsaerts hit the turn in 30 after birdieing four of his first six holes and picked up a further three shots on the back nine to complete a flawless second round that moved him onto 14 under for the competition.
Porteous slid down to 27th with a four-over 75, with Luiten only two shots better off than the South African as their hopes of claiming the $7million prize took a severe hit.
Eddie Pepperell is now the closest challenger to Colsaerts after a birdie-birdie finish put him on 10 under, with Kiradech Aphibarnrat a shot back in third.
Padraig Harrington produced a remarkable par save on the par-three second, playing a chip while pressed up against a tree with the ball lying behind him, but a trio of bogeys on the back nine proved costly.
Matthew Fitzpatrick rose into a four-way share of fourth with the help of an eagle at the 15th and Race to Dubai leader Tommy Fleetwood's one-under 70 leaves him down in joint-38th.
