Woodhall Spa United stunned Skegness Town Reserves as they won 2-1 in the Barclays Brokers Willoughby Cup.
Spa travelled to the coast to face a side which is currently fourth in the Boston Taylors Service Garages Premier Division - the league above Woodhall - but came away with a stunning result to set up a semi-final appearance against Kirton Town.
Kirton also play in the Premier Division but are struggling in 11th place.
The tie will be played at Graves Park, Kirton, on March 29.
Mareham United fell to a 4-1 defeat against Billinghay Athletic in the Premier Division.
The Fieldsiders went into the fixture on the back of two big wins but faced a tougher test as they went up against the team sitting third in the league.
Unfortunately their good run of form came to an end as their defence came unstuck on four occasions.
Mareham face an even tougher test this weekend as they travel to top of the league Wyberton who are currently 10 points ahead of Swineshead Institute in second place.
AFC Tetford ended their season with a 3-3 draw at Park United.
Tetford are currently second in Division Three, 13 points behind Boston College who look set to win the league.
The East Road side’s fate is out of their hands as FC Kirton could leapfrog them with two games in hand, as could Swinshead Institute A who have four games in hand.