Scott Jamieson produced a stunning seven-under-par 65 to claim a two-shot after the second round at the KLM Open.
The Scot has won only once on the European Tour, back in 2013 at the Nelson Mandela Championship, but surged to the summit courtesy of seven birdies to sit at 11 under par in Amsterdam.
Sergio Garcia leads the chasing pack at The International, carding six birdies and a bogey in his five-under-par 67 to join English trio James Morrison, Callum Shinkwin and Matthew Southgate at nine under.
Another Englishman Sam Horsfield mixed eight birdies, five bogeys and five pars in his roller coaster 69 to reach eight under alongside 18-year-old Dane Nicolai Hojgaard.
Paul Dunne is the leading Irish challenger after carding a 69 to leave him on four under, with Gavin Moynihan one shot further back. Padraig Harrington's second consecutive 71 saw him make the cut by the slimmest of margins.
"It was a great day." Jamieson told europeantour.com.
"I was really good with my irons yesterday but wasn't so good off the tee, and today I was better off the tee and equally as good with my irons.
"I think it is a second shot golf course for sure. You just need to pick the right shot and execute it. I don't think it is a course you can overpower so hopefully I can think my way around it."
Morrison set the clubhouse target on Friday morning courtesy of two eagles in the space of four holes, as well as five birdies, two bogeys and a double bogey in an entertaining 67.
Overnight leader Shinkwin carded four birdies in 14 holes to move back ahead and reach 10 under, only to register two bogeys - including a shoehorn par putt at the last - and a gain in his final four holes to squander the solo lead before Jamieson powered to the top.
Garcia moved to within one shot of Morrison and Shinkwin thanks to birdies at the first, seventh, eighth, 14th and 15th after dropping a shot at the sixth.
The Spaniard produced a remarkable par save at the 17th with a sublime chip to close range and hit an equally impressive second shot at the par-five last, but his eagle putt rolled up inches short - which would have taken him to second.
Southgate holed six birdies and two bogeys to join Garcia, Morrison and Shinkwin in a tie for second, one shot ahead of Horsfield and Hojgaard.