Scott Hend carded a superb 63 to surge into the lead of the European Masters at the halfway stage, while Darren Fichardt matched his score for the round to sit one stroke adrift.
The Australian suffered heartbreak as he lost in a play-off with Alex Noren in Crans Montana last year, but he is brilliantly placed to make up for that disappointment this time around.
Hend held a share of the overnight lead with Miguel Angel Jimenez and Tyrrell Hatton but, while he went from strength to strength, Jimenez and Hatton both faltered.
Jimenez dropped back to three-under-par with a three-over 73, while a 71 for Hatton saw him fall to five under.
Hend, though, gained seven strokes in a flawless round to lead Fichardt - who also carded a 63 - by one stroke.
A magnificent tee shot to three feet helped Hend to an eagle at the seventh, before he made the turn in 32 after a birdie at the ninth. He then finished in spectacular fashion with four birdies in the final five holes.
Hend's performance came despite the significant distraction of having his children home in Florida, where Hurricane Irma is set to land.
The 44-year-old, whose wife is serving as his caddie in Switzerland, said: "We're a bit worried about the kids in Florida with the sitter at the moment.
"We've been up late at night trying to find out contingency plans. I think they're going to get out of there. It's not worth the risk."
Fichardt matched Hend's round with five birdies and an eagle, which came at the 15th, as the South African followed up his opening round 65 in style.
Thongchai Jaidee, Fabrizio Zanotti and Todd Sinnott are all four strokes back on nine under, with Matthew Fitzpatrick five off the pace along with Julian Suri and Ryan Fox.
Defending champion Noren improved on his level-par round one with a three-under 67 but still has plenty of ground to make up to have any hope of retaining the title.
Lee Westwood, making his 500th European Tour appearance, made the cut thanks to three birdies in the final five holes having been one over after 12.
World number 16 Tommy Fleetwood did not make the cut, however, his level-par round not enough, the Englishman having carded a 72 a day earlier.
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