Ayr United made it six points out of six with two late goals securing a 3-1 win over Dumbarton in League Cup Group E.
Andy Dowie's own goal gave the visitors the lead before Dumbarton hit back through Christian Nade.
Two goals in the last 20 minutes from Declan McDaid and Robbie Crawford kept Ian McCall's men three points ahead of Ayrshire rivals Kilmarnock.
Killie were 4-2 winners over Clyde to gain their first points of the group.
Rory McKenzie gave Killie an early lead before Darren Ramsay and Kevin Nicoll edged Clyde in front.
That is how it stayed until 53 minutes when summer signing Dominic Thomas scored, with the former Motherwell man adding his second soon after.
After McKenzie scored again to make it 4-2, Jordan Stewart was sent off for the visitors following a late challenge to curtail any hope of a Clyde comeback.
In Group F, Greenock Morton scored twice in the final five minutes before beating Queen's Park 4-2 in a penalty shootout.
The Spiders had taken the lead through Bryan Wharton with 20 minutes to go, and when Thomas Orr scored with nine minutes left it looked to have earned the League One side a shock win.
Bob McHugh turned in Scott Tiffoney's cut-back to set up a frantic finale, and Darren Barr's volley two minutes into time-added-on took the game to penalties.
Morton won the bonus point to stay top of the group on five points with Tiffoney, Andy Murdoch, Ricki Lamie and Gary Harkins all scoring from the spot for the hosts, with Adam Cummins and Bryan Wharton netting for the visitors.
Elsewhere in Group F, Berwick Rangers also needed a late goal in the 90 minutes, but lost 4-2 on penalties to Edinburgh City.
Ashley Grimes had twice given Edinburgh the lead but goals from Aaron Murrell and Pat Scullion pegged them back.
The capital side won the shootout after Chris MacDonald and Andrew Irvine missed for Berwick.