Crusaders's Premiership advantage was trimmed to four points as they had to settle for a draw against a committed Dungannon side at Stangmore Park.
With second-placed Linfield beating Ballymena, Crues were left to rue a series of missed chances before Ryan Harpur put the Swifts ahead on 57.
Paul Heatley levelled for the leaders on 60 but they failed to convert other late chances as the Swifts held firm.
Linfield also have a game in hand on Stephen Baxter's side.
Crusaders had gone into the contest after a run of seven straight wins although Dungannon had also produced good recent form of their own having earned 10 points from a possible 15.
The leaders were unchanged from their 6-0 destruction of Portadown and they could have put the game to bed in the opening 15 minutes as Gavin Whyte shouldn't have allowed Andy Coleman to make a fine save and the keeper then denied the impressive Richard Clarke.
The loss of defender Josh Robinson appeared to briefly ruffle the Crues as Harpur hammered a Swifts chance wide.
However, the Crues quickly regrouped to create further great chances with Jordan Owens blasting a glorious opportunity over the crossbar and then heading a Clarke free-kick across the face of goal.
Crusaders continued to press after the break with Coleman grasping a Colin Coates header and Heatley then firing wide as snow started to fall.
However, teams that miss such a catalogue of chances are invariably punished at the other end and so it proved in the 57th minute as Harpur's deflected shot trickled past a wrong-footed Sean O'Neill.
To their credit, Crusaders did get on terms within three minutes as Heatley ran on to an Owens flick-on to fire past Coleman.
However, Dungannon refused to buckle in the closing half hour although they did benefit from some more imprecise Crusaders finishing.
Coleman did well to save Heatley's 65th-minute snapshot while Declan Caddell connected to head over Heatley's fierce cross-shot over the bar although the Crues midfielder knew little about the effort.
Dungannon, from whom keeper Coleman and defender David Armstrong excelled, continued to have their moments in the closing stages as Jamie Glackin's deflected effort had to be tipped over by O'Neill.