Kilmarnock beat Dundee United 2-1 at the BBSP Stadium, Rugby Park to book their place in the last four of the Premier Sports Cup on the weekend of January 14/15.
Kyle Lafferty's early penalty was quickly cancelled out by Glenn Middleton but Daniel Armstrong headed the winner from a Jordan Jones cross with 17 minutes left.
The remaining quarter-finals are being played on Wednesday evening, followed by the semi-final draw - it will be shown live on Premier Sports after their coverage of Rangers v Dundee.
