Victoria were cruising to victory, reducing Queensland to 6-79 and 8-145 before Swepson and debutant paceman Xavier Bartlett combined to conjure the unlikeliest of counter-attacks.
Like the RAAF SuperHornets that regularly cruised the Townsville skies near the venue during the day, the Bulls roared back into contention to need 19 runs of just five overs.
They ultimately fell 13 runs short, dismissed for 227 from 46.5 overs.
Bartlett hit the only six of the Queensland innings, opening the account for new charity partner Foodbank Queensland with Queensland Cricket donating $100 for each six hit during the one-day tournament.
Swepson’s score of 77 was a record for a number nine batsman in Australian One-Day Domestic competition history, passing Peter Siddle's record of 62 in 2017.
He and Bartlett (28) put on 77 for the ninth wicket, with Swepson’s run a ball innings taking Queensland to within sight of the Victorian total of 240.
His dismissal, off the third last ball of Chris Tremain’s final over, meant Victoria clinched nervous win, with only spinners Nic Maddinson, Matt Short and Glen Maxwell left to bowl the last overs.
The Bulls will rue the relative lack of runs from the batting line-up, aside from teenage opener Max Bryant who calmly made light of his debutant status to crunch an impressive 45 off 38 balls.
Earlier, paceman Mark Steketee shrugged off a wayward opening over to finish with an impressive 4-37 from 10 overs as he helped make early inroads before helping fight back after a strong partnership between Maxwell (80) and Maddinson (68).
The Bulls were looking down the barrel of conceding a double bonus point before Joe Burns (25) and Steketee (17) stemmed the tide, before Swepson and Bartlett regenerated the innings.
The Bulls will regroup at home, ahead of their next match at Riverway Stadium against Tasmania on Saturday.