The Dons Under 18's hopes of making it five straight league wins were dashed as Livingston gained revenge for their February defeat at the Chris Anderson Stadium.
A second half penalty award, described as soft by the Dons camp, was converted by Scott McLaughlin to give the Lion Cubs a slender 1-0 win against the run of play.
Reflecting on the defeat, Neil Cooper says the match could easily have swung in his side's favour. "I felt we were the better team overall but we paid the price for missing chances. John Stewart missed with a header from only five yards while their keeper had a couple of excellent saves. I thought we'd grabbed an equaliser right at the death when our goalie David Hutton went up for a corner, but a defender managed to block his effort on the line."