Douglas B sent holders Southern Nomads crashing out of the Shimmin Wilson Manx Trophy on Saturday.
A 29-0 win at Port-e-Chee sent the home side into the final.
Daryn Thompson bagged two tries for Douglas with additional tries coming from Niall Killey, Blake Ronald and Seth Waterworth.
Skipper Mark Shortland converted two.
Douglas will now meet Vagabonds B in the final.
Meanwhile, a 40-10 victory against Castletown cemented Emerging Nomads' place in this season’s Shimmin Wilson Manx Bowl final.
They still trail Western Vikings by a single point but will pick up that from their remaining game against Ramsey B, regardless of the result.
Joe Callaghan picked up two tries for Nomads with others coming from Brendan Coleman, Adam Young, Gerard Landels and Al Wilkinson.
Rob Martin kicked five conversions.
Town’s points came courtesy of a penalty try, plus a penalty and a conversion from John Forest.