Unseeded Dane Kristian Frost Olesen produced the biggest upset in the Pilatus Cup when he ousted third seed Gilly Lane in a marathon first round battle in the inaugural PSA World Tour Challenger 10 squash event at Sportpark Pilatus in the Swiss town of Kriens.
After enduring two tie-break games which lasted almost an hour, the 22-year-old from Odense edged out Lane, ranked 16 places higher in the world, 10-12, 12-10, 11-7, 6-11, 11-5 in 90 minutes.
"I am my pleased to get through to the quarter-finals," said Olesen later. "It was a very hard match with Gilly and I am just happy that I pulled through in the end after a terrible game."
Olesen will now face fellow non-seed Lewis Walters after the 23-year-old Englishman disappointed the local crowd by beating wildcard player Reiko Peter, from nearby Luzern, 11-9, 10-12, 11-5, 15-13.
But German qualifier Andre Haschker also secured a surprise quarter-final place after upsetting England's higher-ranked Tom Pashley 11-4, 11-7, 12-10.
The Dresden-born 28-year-old will now line up against Stephane Galifi, the No2 seed from Italy who beat New Zealander Kashif Shuja 11-7, 11-4, 11-3.
"The good old diesel is still running," said the delighted Haschker afterwards. "Also I could feel that Tom's movement wasn't smooth today so I tried to exploit it.
"Tomorrow I play two-seeded Stephane Galifi. It's an honour for me to play such a big character in the quarterfinal. I will give all I have left in the tank."
RESULTS: PSA Challenger 10 Pilatus Cup, Kriens, Switzerland
 Chris Simpson (ENG) bt [Q] Jonas Daehler (SUI) 11-5, 11-3, 11-7
Steve Finitsis (AUS) bt Amr Swelim (ITA) 11-4, 11-7, 6-11, 5-11, 11-8
Lewis Walters (ENG) bt Reiko Peter (SUI) 11-9, 10-12, 11-5, 15-13
Kristian Frost Olesen (DEN) bt  Gilly Lane (USA) 10-12, 12-10, 11-7, 6-11, 11-5
 Julien Balbo (FRA) bt Dylan Bennett (NED) 11-8, 11-6, 4-11, 11-3
[Q] Rasmus Nielsen (DEN) bt [Q] Lucas Serme (FRA) 11-5, 7-11, 11-5, 11-3
[Q] Andre Haschker (GER) bt Tom Pashley (ENG) 11-4, 11-7, 12-10
 Stephane Galifi (ITA) bt Kashif Shuja (NZL) 11-7, 11-4, 11-3
 Chris Simpson (ENG) v Steve Finitsis (AUS)
Kristian Frost Olesen (DEN) v Lewis Walters (ENG)
 Julien Balbo (FRA) v [Q] Rasmus Nielsen (DEN)
 Stephane Galifi (ITA) v [Q] Andre Haschker (GER)