Leigh Griffiths was on target as Celtic defeated Dundee 4-2 at the Kilmac Stadium at Dens Park while Motherwell ran out 4-1 winners against Morton at Cappielow.
Substitute John Robertson hit a hat-trick as St Johnstone thrashed Queen of the South 6-0 at McDiarmid Park. There was also a hat-trick in the other Group B game as Bruce Anderson netted three goals in a 4-1 win for Aberdeen over Ross County at Balmoor.
Callumn Morrison was among the scorers as holders Heart of Midlothian beat St Mirren 3-1 at Meggetland while Hamilton Accies defeated Dundee United 1-0.
Reserve Challenge Cup
In the West Section, Airdrieonians thrashed East Kilbride 5-0 and Albion Rovers and Ayr United drew 1-1, with Ayr winning the penalty shoot-out 11-10 for the bonus point.