Dumbarton, Alloa Athletic, Ayr United and Motherwell U20s won to reach the second round of the Scottish Challenge Cup.
The Sons overcame Rangers U20s 2-1, while Ayr were comfortable 5-1 victors away to East Stirlingshire.
Alloa claimed a 4-2 win against hosts Dundee U20s.
And Motherwell U20s were the only colt team to triumph in Wednesday's ties, beating League One side Queen's Park 2-1.
The Spiders had led through Adam Cummins but Ellis Plummer and Adam Livingstone netted to turn the match in Well's favour.
Mark Stewart scored what proved to be Dumbarton's winner, with Callum Gallagher converting an earlier penalty and Ryan Hardie replying for Rangers.
Alan Forrest was among Ayr's scorers against Shire and Craig Malcolm notched two of Alloa's goals.
On Tuesday, there were wins for Aberdeen, Hamilton Academical, Partick Thistle and Ross County's U20s sides while holders Dundee United were among the Championship sides to progress.
The draw for the second round will take place in Falkirk on Thursday.
The 24 first-round winners will be joined by Northern Irish sides Linfield and Crusaders, Welsh clubs The New Saints and Connah's Quay Nomads, and Republic of Ireland's Sligo Wanderers and Bray Wanderers in round two.
Challenge Cup results
First round north - Dundee U20 2-4 Alloa Athletic
First round south - Dumbarton 2-1 Rangers U20, East Stirlingshire 1-5 Ayr United, Motherwell U20 2-1 Queen's Park