The Gaffer gave his reaction to the 1-0 defeat at Oakwell.
The Reds Head Coach told the press in the aftermath of the defeat that he felt a mixture of emotions.
Despite dominating the game throughout, the Reds struggled to test visiting 'keeper Allan McGregor and were then dealt a sucker punch as Hull grabbed the winner from a corner.
The Gaffer said: "I said to the players afterwards that I'm upset for them and angry with them. But overall I just felt really disappointed.
"When we're not taking our chances at one end, we're going to get punished. We stopped them creating hardly anything in open play. They've done us with a set play.
"The game was scrappy in parts but we had numerous attempts at goal and weren't ruthless enough again. We have to be better in both boxes, as I've said before."
Heckingbottom altered the team's formation for this match, and whilst on the end of a disappointing result, he believes he saw positive signs for the future.
"We've been working on 4-4-2 for a couple of weeks," he told us. "We tried it on the day and I felt it would make us defensively stronger against Hull, especially out wide where they have real threats. And it did that.
"There were good bits in the performance and of course, areas where we need to improve in. It's the nature of the squad and this division I suppose, it's difficult to predict.
"But whilst we've lost the game, we still felt we were more than competitive."
The Reds now move on to Saturday's South Yorkshire against Sheffield Wednesday and Hecky says focus has quickly switched to what is always one of the most exciting games on the calendar for fans of both clubs.
"I'm looking forward to it, definitely. The Hull game is done, out of the way, so we're focused on the Wednesday game.
"It's one we always enjoy, home or away. And it's a new occasion for lots of our players again, so we'll have to prepare them well and make sure they know exactly what this game can be like, the atmosphere and how much it means."
Paul Heckingbottom's reaction is available to see over on iFollow.