An extra-time strike from Ben Binder steered FC Team B into the final of the Barry Goldstein Trophy following a 5-4 win over Norstar London Raiders B.
Team came from behind twice in a real thriller, with Richard Salmon, Andy Sheena and Binder on target, while 'keeper David Grossman converted his fourth goal of the season from the penalty spot.
Team boss Mitch Young said: "We're delighted to reach our first final at Wingate and I am extremely proud of everyone.
"Credit must go to NLR for their display in an outstanding game between two committed and well organised clubs who gave their all for a place at the Harry Abrahams Stadium.
"The boys showed unbelievable character, commitment and passion, and they deserve all the credit as NLR are a top side. They have only lost a couple of games in two seasons, so to progress to the final is a huge achievement. Now we are looking to finish the season with the double."
Los Blancos won the other semi-final, edging home 3-2 against Camden Park.
Trailing by two goals at the break, the introduction of substitutes Joel Kutner and Jeff Gross inspired a dramatic comeback.
Adam Waters and an 85th minute penalty from top-scorer Simon Moses hauled Blancos back on terms, and it was left to Gross to convert the winner deep into stoppage time.
Blancos boss Jonathan Ison said: "The boys are buzzing after guiding the club into its first final since we were set up five years ago.
"I have been comparing us to Liverpool since the beginning of the season. On the day, with both teams in their respective semi-finals, both were very poor. However, Blancos were able to turn it around in the second half and show what we are made of."
Looking ahead to the final, he went on to say: "FC Team B are clearly a good side and have had a great season, but we know we are a match for anyone on our day. We're going to Wingate confident of ending our long wait for silverware."