Morton reached the third round of the CIS Cup for the first time in 11 years after a thrilling 4-3 victory over Hibernian.
Morton are second bottom of the Scottish First Division and had to travel to the Scottish Premier outfit but sensed an upset after Ian Russell and Steven Masterton gave them a 2-0 lead heading into the closing stages.
Joe Keenan's 80th-minute strike gave Hibs hope before Dean Shiels struck five minutes later to send the game into extra-time.
Morton's hopes looked to be dashed when substitute Steven Pinao gave Hibs the lead just a minute into extra-time.
But Russell equalised with a 115th-minute penalty before Ryan Harding grabbed a sensational winner just three minutes from time.
Runners-up safely through
Last year's runners-up Dundee United sealed their place in the next round with a 5-1 victory at Cowdenbeath.
Jon Daly hit a hat-trick for the SPL outfit while David Goodwillie bagged a brace, and John Dempster claimed a late consolation.
St Mirren also progressed against Third Division opposition by cruising to a 7-0 drubbing of Dumbarton.
Billy Mehmet hit a hat-trick while Steven Robb, Andy Dorman, Craig Dargo and Gary Mason were also on target.
Falkirk are still without a point in the SPL but put their league problems behind them with a 3-1 win at Raith.
Michael Higdon and John Stewart (penalty) scored for Falkirk in the first half, and although Mark Campbell pulled one back with 16 minutes left, Mark Stewart sealed it late on.
The other SPL team to go through was Hamilton after a 3-1 home win against Clyde.
James Grady's 17th-minute opener for Hamilton was cancelled out two minutes later by Patrick Clark, but Joel Thomas and Tony Stevenson (penalty) struck late on after Clyde had defender Michael Ohnesorge sent off in the 66th minute.
Partick Thistle prevailed in the battle between the First Division's top two with a 2-1 win at Dundee.
Ian Maxwell broke the deadlock for Partick in the 78th minute, and although Paul McHale equalised two minutes later, Gary Harkins won it with an 87th-minute penalty.
Livingston progressed in another all First Division-clash, beating St Johnstone 2-1 after extra-time.
Liam Craig gave the hosts a 46th-minute lead, and although Leigh Griffiths claimed a 58th-minute equaliser, Jean-Jose Cuenca settled the tie in the 95th minute.
Elsewhere, Andy Kirk's eighth-minute strike was enough for Dunfermline to beat Alloa 1-0.