Lawrence Shankland netted a hat-trick as Ayr United came from behind to beat Greenock Morton at Somerset Park.
The visitors drew first blood in the Scottish League Group E clash, Michael Tidser putting Morton ahead after 14 minutes.
Shankland equalised early in the second half before firing two goals in three minutes to seal the win.
In the day's other Group E match, Partick Thistle saw off League One side Stenhousemuir 2-0 at Ochilview.
The newly-relegated Championship side did the damage early, on-loan Motherwell midfielder Shea Gordon scoring twice in the opening five minutes to give Thistle a lead they would maintain until the end.
Palmerston played host to an extraordinary Group G match between Queen of the South and Stranraer. The League One outfit stunned their Championship rivals by racing into a two-goal lead inside nine minutes, with Chris McGowan and Luke Donnelly finding the net.
However, Gary Harkins and Stephen Dobbie hit back to level things up and Lyndon Dykes capped a crazy opening 45 minutes by putting Queens in front just before the break.
Andy Stirling made it 4-2 to the home side before Kyle Turner responded for Stranraer. However, Dobbie completed the scoring to make it 5-3 and secured the points for Queens.
In the other Group G clash between League Two rivals Clyde and Edinburgh City, Conrad Balatoni's goal just before half-time gave the visitors the lead, only for Martin McNiff to equalise in second-half stoppage time.
City prevailed 4-1 on penalties to claim the extra point.
In Group H, Lowland League side Spartans proved a match for Dumbarton of League One, but ultimately went down 4-3 on penalties after a goalless 90 minutes.
Dumbarton's two points moves them level in the group with St Mirren after their shootout victory over Kilmarnock on Friday night following a 0-0 draw at Rugby Park.
Ayr United 3-1 Greenock Morton
Stenhousemuir 0-2 Partick Thistle
Clyde 1-1 Edinburgh City (Edinburgh City won 4-1 on pens)
Queen of South 5-3 Stranraer
Spartans 0-0 Dumbarton (Dumbarton won 4-3 on pens)