Brechin City shocked St Johnstone with a penalty shoot-out victory at Glebe Park.
The match ended 1-1 and then the hosts took the extra Betfred Cup bonus point with a 4-2 spot-kick win.
Chris Kane and Michael Coulson both missed their penalties for the Perth club.
Saints are still strong favourites to win their group – they face Stirling Albion at home on Saturday – but had been hoping to seal the deal in Angus by making it three wins out of three.
City still have an outside chance of qualifying but require a win against Falkirk and other results to also go their way.
The hosts took an early lead through ex-Saint Andy Jackson
He nipped in between Steven Anderson and Tam Scobbie to nod the ball beyond Zander Clark.
Saints boss Tommy Wright introduced Blair Alston at half time and the visitors raised their game after the re-start.
Several chances were squandered before the breakthrough eventually came when Graham Cummins headed a deep cross back into the six yard box where Kane was waiting to bundle the ball home and set up the penalty shoot-out.
