Treble-chasing Skegness Town were knocked out of their stride by a resolute Horncastle Town at the Wong.
Having beaten their East Lindsey rivals three times already this season, the Lilywhites began as favourites to progress to the Challenge Cup final.
But Horncastle had other ideas and, thanks to a Jasper Caudwell goal just before half time, the Wongers squeezed through to the final, where they will meet Brigg Town Reserves on April 12.
The seasiders, after missing a couple of early chances, struggled in a scrappy and often bad-tempered local derby.
Frustration got the better of them far too often and the Wongers found it easy to dampen their threat.
This was the first time the Lilywhites have failed to score this season, but Horncastle worked hard to repel the danger.
The seasiders have nudged them out of the title race this season and in December knocked them out of the Lincolnshire FA Junior Cup, but they didn’t have enough in their armoury to force this tie into extra time.
The closest they came to an equaliser was a fierce drive from Will Britton in the 80th minute, which Horncastle keeper Lewis Burchnall blocked with his legs.
Skegness launched a number of long balls into the home penalty area for Ben Davison to scrap for, but nothing fell kindly for them.
When Andy Parish did meet a loose ball from one such raid, there were enough bodies wearing the stripes of Horncastle to divert the danger.
The visitors suffered another blow with injury forcing Luke Rayner-Mistry to be replaced at half time.
Moorlands Railway 0
Skegness Town 5
Skegness Town returned to the top of the Lincolnshire League with a 5-0 win at Lincoln Moorlands Railway on Tuesday evening, ending their hosts’ run of 14 straight victories.
The seasiders took the lead midway through the first half when Will Britton broke down the right and crossed for Alex Nichols to tap home.
Another close range effort from Nichols doubled the seasiders’ lead.
Nichols grabbed his hat-trick eight minutes into the second half before Britton added a brace, his first from the spot.
The Lilywhites are now top on goal difference from Hykeham Town, but with two games in hand.