Alan Trouten's disputed penalty in the 109th minute was the tie's decisive moment to send Alloa into the quarter-finals but Neilson insists his team should have been out of sight long before then.

He said: "We should have scored, the amount of chances we had, the positions we got into where we should have scored.

"That's the reason we didn't progress in the cup.

"We have to go away and we have to work on it and we have to look at the final moment and the concentration in the final moment.

"It was a disappointing day for us, a very disappointing day."

Neilson's frustrations boiled over at full-time when he was given a yellow card for his protests at the winning penalty.

Hearts claimed there was no contact when Jamie Walker challenged Alloa substitute Robert Thomson in the box, but referee Gavin Duncan saw enough to award the spot-kick.

Alloa are bottom of the Championship without a win in five league outings but held firm for a first-ever victory over Hearts.

In fact, they created the game's most clear-cut opportunity when Craig Gordon had to turn Liam Buchanan's header round the post 17 minutes from the end of regular time.

Referencing the often-used criticism of their artificial surface and anticipating Hearts' complaints over the penalty, Alloa manager Peter Grant said: "People will probably blame the pitch or referee. Sometimes you have to take your medicine and get on with it.

"I thought as a group we worked so hard out of possession. A lot of people will say we play good football and that's nice to hear, but you need to work so hard and we did that.

"Maybe I need to look at myself as I forget these boys are working their socks off at their own job doing all sorts of shifts.

"When Hearts were getting a rub and a massage some of our boys were out working at three o'clock in the morning.

"That tells you enough, but the boys showed that desire and got the result."