Hibernian were stunned by League 1 Kelty Hearts as Callum Flatman's header defeated the Premiership side in Scottish League Cup Group C.
David Gray's side could not recover from the 58th-minute opener at New Central Park as he sustained his first loss as Hibs head coach, though they remain top of their group.
Aberdeen made it two wins out of two under new head coach Jimmy Thelin, scoring four without reply away to East Kilbride.
Three more Premiership sides, Motherwell, Ross County and St Johnstone, enjoyed wins against Clyde, Raith Rovers and Morton, respectively.
Airdrieonians, Alloa Athletic, Annan Athletic, Falkirk, Hamilton Academical, Inverness Caledonian Thistle, Livingston, Partick Thistle and Peterhead all secured victories.
First-half strikes by Nicky Devlin and Jamie McGrath put Aberdeen well in control at K Park and Leighton Clarkson's second-half free-kick and Shayden Morris' effort made sure of victory.
Airdrie trailed Dumbarton 3-1 but recovered to win 4-3. James Hilton scored twice for the Sons after Lewis McGrattan had cancelled out Finlay Gray's opener. Rhys Armstrong, Terrell Agyemang and Ben Wilson scored in the final quarter to move the Diamonds top of the group, ahead of Aberdeen on goal difference.
Aidan Nesbitt, twice, Sean Mackie and Ryan Shanley all scored for Falkirk after Ryan Fyffe's own goal opener had been cancelled out by Buckie Thistle's Andrew MacAskill.
Dundee United host Ayr United in the evening kick-off.
Flatman, formerly of Hearts, nodded high into the net from former Hibs midfielder Scott Allan's delivery to break the deadlock at New Central Park. Kelty are two points off Hibs.
Ben Armour put Peterhead in front against Elgin City but Jack Murray's strike and Dajon Golding's penalty turned the back in the visitors' favour. Caleb Goldie restored parity and Jason Brown's double secured a 4-2 win for the hosts.
Tommy Goss headed Annan in front away to Arbroath and the hosts had Scott Stewart sent off for violent conduct before half-time. Josh Dixon and Josh Todd added second-half goals for the visitors.
Inverness also won 3-0, with Adam Brooks, Keith Bray and Luis Longstaff all netting for Duncan Ferguson's side in the first half.
Leaders Annan are a point in front of Dundee and four ahead of Inverness.
There was only one goal in Livingston with Robbie Muirhead striking for the Lions after 11 minutes.
Forfar Athletic and Cove Rangers were tied 1-1 after 90 minutes, with Connor Scully cancelling out Blair Malcolm's opener for Forfar. Forfar prevailed 3-1 on penalties and they and Livi have six points, three more than third-placed Spartans and Dunfermline Athletic.
Benjamin Mbunga Kimpioka struck twice in the first half to give St Johnstone a comfortable 2-0 win against Morton in Perth.
At Glebe Park, Alloa built a 3-0 lead through Scott Taggart's early penalty and second-half goals from Kevin Cawley and Luke Rankin before Marc Scott's late consolation. Alloa trail leaders Saints by a point.
Motherwell led through Moses Ebiye's early goal but Lee Hamilton brought Clyde level in the second period. Lennon Miller's penalty and Filip Stuparevic's late strike gave Well a 3-1 win and eight points at the top of the group.
Partick Thistle are second on six points after a 6-0 win away to Edinburgh City. Scott Robinson, Brian Graham, Harry Milne, Ricco Diack, Wasiri Williams and Kyle Turner all scored in the second half.
Jordan White headed County in front before the break in Dingwall but Callum Smith brought Raith Rovers level soon after the interval. George Harmon settled the match with three minutes left. Raith still lead County on goal difference at the top of the section.
At Stair Park, Hamilton took the lead through Steven Bradley, an advantage that was added to by Kyle MacDonald and Euan Henderson in the second half. Hamilton are two points off the top two.