Ramsey will meet holders Douglas on April 27 after two contrasting Manx Cup semi-finals on Saturday.
Favourites Douglas easily brushed aside the challenge of Southern Nomads with a comprehensive 65-0 victory.
However, there was something of a surprise in the other with Ramsey just edging Vagabonds out 24-18 – the third time they have beaten them this season.
Douglas put in another impressive performance to underline their dominance this season.
Bryn Snellgrove, Jack Lea and Callum Carine all bagged two tries apiece as Douglas raced into an early lead.
There were further scores from Mike Hebden, James Wood, Craig McGee, Daryn Thompson and skipper Scott Goodall who also kicked five conversions.
At Ballafletcher, it was Vagabonds who led early on through a Kevin Birchall try.
Ramsey went ahead when Fintan Cummins converted Lance Wyllie’s try and they held onto their slender 7-5 lead until half-time.
A Leigh Kennaugh penalty early in the second half put Vagas in front, but a Mark Oldfield try and another Cummins conversion gave it back to Ramsey.
Rob Martin went over to bring Vagas to within a point but Cummins was on target with a penalty at the other end leaving Vagas needing a try to take the game in the last few minutes.
Ramsey countered and a John F Watling try, converted by Cummins, gave them a 24-13 lead.
Although Vagas picked up a late try from Luke Purdy, it wasn’t enough.