Southampton youngster Dynel Simeu returned for Saints B for their 2-2 draw at Birmingham City.
Dom Ballard opened the scoring from the spot and defender Will Armitage thought he had won it late after Joshua Williams had equalised for Blues in the second-half.
But Birmingham levelled versus Dave Horseman's already confirmed group winners deep into injury time.
Simeu was called upon by Horseman despite his season-long loan at League Two Tranmere Rovers, which he will return to following Saints duty.
He is currently serving a suspension for a straight red card picked up last month, but is eligible to play in non-first-team games while out on loan.