ST IVES Town of the Jolly's Cornwall Combination League caused the major upset of the quarter-finals when they earned a dramatic penalty shoot-out victory over SWPL Division One West high fliers and cup favourites Helston Athletic at The Saltings.
The home side came into Saturday's game occupying fifth spot in the Combination League but still smarting from a shock 3-0 home league defeat to Mullion only a week earlier.
But they made the perfect start to Saturday's cup tie when they were awarded a penalty with only seven minutes on the clock, after Martyn Harding had been fouled in the box.
Martyn Moon netted the resulting spot kick to give the Saints a lead which they held until five minutes from the end of normal time, when Helston striker Mark Goldsworthy turned in a cross from former Penzance winger James Miller to force another half-hour.
With no further goals in extra-time, the game went to penalties and after each side successfully converted three apiece, keeper David Chard was to prove the hero for the Saints, saving Helston's last two spot kicks before former Conference striker Ian Hodges scored the winning penalty to ensure his side a place in the semi-finals.
Elsewhere, Wadebridge Town also booked their place in the semi-finals after overcoming a potential upset against East Cornwall Premier League outfit Bude Town.
It did take extra-time for the Bridgers to eventually see off the challenge of Town though.
Wadebridge took the lead within a minute through Liam Ames, but a second half free-kick from Dave Youlden sent the game into extra-time.
Two goals from Dan Jennings made it 3-1 to Wadebridge, before a Youlden penalty made for a nervy finish as the SWPL side held on for the win.
Dobwalls were 5-2 winners at Porthleven in their quarter-final clash.
They had to come from behind after Port's Freddie Williams had given the hosts the lead. That was soon cancelled out by Jack Bartlett and they then took the lead through Joe Knight.
Simon Skews added a third goal for Dobwalls after the break, before Porthleven hit back through Williams.
The visitors, though, made sure of victory with goals from Dan Lawrence and a Skews penalty.
In SWPL Division One West, Hayle held in-form Callington Town to a goalless draw at Hayle on Saturday.
Lee Beer's men have failed to score twice this season and on both occasions it has been against Hayle.
Strike duo Andy Sargent and Ryan Lucassi had Callington's best chances to score, only to be denied by Hayle goalkeeper Danny Burrows.
Hayle face another tough test this Saturday when they travel to league leaders Godophin Atlantic, while Mousehole also make a return to action at home to Perranporth (both matches kick-off at 3pm).