A first-half effort from Louie Basso steered double-chasing Manchester Maccabi 1st into the semi-finals of the Peter Morrison Trophy following a 1-0 win over Leeds Maccabi 1st.
Manchester will host North London Raiders A this Sunday for a place in the final against Faithfold A on May 15.
Manchester manager Stuart Delmonte said: "We know that will be a very difficult game.
"You don't get to the last four unless you're a good side so we're expecting a tough encounter."
Republic of Mancunia will claim their first ever MJSL title on Sunday as long as they avoid defeat against championship rivals Manchester Maccabi 3rd at Brooklands.
They came from 2-0 down to beat Sporting JLGB 3-2 courtesy of a hat-trick from Dave Eden.
Oakhill Lions grabbed three points after seeing off Westdene 2nd 2-1 thanks to goals from Dan Cohen and Harry Roache.