Douglas Royal overturned a half-time deficit to reach the GH Corlett Woods Cup semi-finals on Saturday.
They trailed Colby 2-0 at the break after the southerners took control through Tom Crawley and Jamie Heeney.
However, Brett Alcotte was sent-off at the start of the second half for the home side and Royal took full advantage in a tie of two halves.
A Chris Anderson double and Paul Whitley goal sealed an impressive 3-2 win.
Craig Taylor was the star of the show as Onchan won 8-0 at Braddan.
He hit four and was joined on the scoresheet by Mark Reece (two), Stuart Faragher and Craig Marsh as Onchan turned on the style.
Two late goals from substitute Liam Bowley ensured Gymns saw off battling Douglas and District to book their place.