A controversial penalty helped Old Boys inflict a first defeat of the season on St George’s to send them out of the Cu-Plas FA Cup on Saturday.
Craig Stewart netted the spot-kick 15 minutes from time to fire the Blackberry Lane side to a 2-1 victory.
Gary Quirk had opened the scoring for the home side before Callum Morrissey equalised for the holders but Stewart’s penalty ended the Geordies’ Grand Slam hopes.
Old Boys will travel to Laxey in the semi-finals after they won 2-1 at runaway Second Division leaders St John’s.
The Miners showed their top-flight experience with goals from Danny Rose and Darren Hudgeon firing them into the lead.
Nick Hurt pulled one back for St John’s but Laxey held on as the westerners went down to their first defeat of the campaign.
A first half super show from St Mary’s put Castletown to the sword at Springfield Road.
The Saints went on the rampage by hitting six without reply in the first half, emerging 7-1 winners in the end.
A Marc Priestnal hat-trick and doubles from Tom Weir and Martin Reilly did the damage with Mike Williams notching the Town consolation.
St Mary’s will meet Rushen in the other semi-final after the reigning league champions won 6-1 at Second Division Ramsey Youth Centre.
Josh Kelly (two), Adam Cregeen, Justin Hawley, Daniel Pownall and Jordan Watterson were the southerners’ marksmen.
In the Canada Life Premier League, Gymns’ relegation worries increased as they went down 4-1 at home to Peel - Johnny Myers, Gary Christian and Terry Rigaux (two) the scorers for the westerners to keep alive their outside title hopes.
Two clubs comfortably in mid-table, Ramsey and Corinthians, fought out a goalless draw at Ballacloan.