Hearts manager Robbie Neilson claimed a combination of sloppy finishing and a bad refereeing decision cost his side in their shock 1-0 Betfred Cup defeat to Championship strugglers Alloa.
The Championship favourites fell to their second loss of the season, thanks to Alan Trouten's penalty in the second-half of extra-time.
The Tynecastle side dominated possession for most of the tie but failed to breach a stuffy Wasps defence and paid the price when referee Gavin Duncan penalised Jamie Walker for a foul on Alloa substitute Robert Thomson in the 109th minute.
Neilson, who was yellow-carded for his protests after the full-time whistle, said: "We dominated the game, we should have won it by two or three goals at least, but we didn't take the chances and got done at the end by a bad decision.
"I didn't think there was contact at the time, I've seen the replay and there's none at all. You'd hope you'd get a referee who'd see that but it ends up being the pivotal moment in the game.
"But the most frustrating thing is we shouldn't have been in that position in the first place. We dominated the play.
"I always felt we could get a goal the longer it went, and we should have scored, the amount of chances we had, but that's why we didn't progress.
"I spoke to the ref but at the end of the day he's made a bad decision. When he looks back he'll realise he's made a bad decision and hopefully he learns from it."
Alloa counterpart Peter Grant hailed his part-time players after they recorded the club's first victory over Hearts – just four days on from a 3-0 loss to the Jambos in the league.
He said: "Some of their players will probably be on more (money) than our squad put together – maybe for the year not just a week.
"Some of the boys were working this morning, one of them until 4.30 am. Going into extra-time, I was a bit concerned about that but they showed the desire and commitment they have, along with their talent.
"They are so talented and, no matter who we play, we try to win, and I think we deserved it.
"Our goalie had a double save but (Hearts goalkeeper) Craig Gordon had the best save of the match. We thoroughly deserved it over the piece."
