Letterkenny man Dale Gorman was on the score-sheet for Leyton Orient on Tuesday night.
Orient defeated Southend 2-0 in their opening group game of the EFL Trophy.
Gorman scored the second with a curling effort into the top of the goal.
Dan Happe scored in the first half.
AFC Wimimbledon and Brighton and Hove Albion U21 are also in the group.