Robert MacIntyre shot a classy 65 to claim a four-shot lead at the European Open.
The 23-year-old followed up his opening round of 68 with a seven-under performance on Friday to surge clear at the top of the Hamburg leaderboard.
Scottish rising star MacIntyre, who is seeking his first title on the tour, will play with world number 924 Bernd Ritthammer in the final pairing on Saturday.
The German went round in 66 to move to seven under, two shots ahead of Paul Casey, who failed to capitalise on an opening 66 as he followed up with a one-over 73 that featured four dropped shots.
"I'm quite happy to be standing here with one over - five under for the tournament," Casey told the European Tour's official website.
"It's such a difficult golf course. Attitude is key and I had a good attitude. Luckily there are some options to get birdies if you stick with it and you hit good golf shots and luckily I made a couple but yeah, very difficult stuff."
World number nine Xander Schauffele had a 69 to move to two under, but fellow Americans Patrick Reed and Matt Kuchar sat two over and four over respectively, Reed making the cut but Kuchar missing out by one shot.
There was no doubting the star of the show at the Green Eagle club, though, with MacIntyre's brilliant bogey-free round firing the Scot into a dominant position.