The Owls still have to play Bristol City next Saturday knowing that their season will be extended in the play-off lottery but a win could determine whether Wednesday play at home or away first.
But Paul Sturrock's men were outstanding at the KC Stadium and that win could give the club the momentum they need to have a confident run in the post season.
Heckingbottom told Footymad: "It feels fantastic to be in the play-offs. With the fixtures coming up for ourselves and other clubs we know we are there so the supporters can start planning, I know some of them have been for a long time and now they can really set their minds on it.
"We needed a big performance. We have had a lot of bad luck in this recent run we have had. We have played well in some of them but not got the breaks we needed. We gave a great performance against Hull and it’s always nice to win it in the last minute. It could be the kick up the backside which we have needed in the last few weeks – you need to be going into the play-offs in good form.
"The fans will treat the Bristol City game as more of a celebration but we have to be very professional and we have to win as you just cannot go into the play-offs with shaky form. We will all be putting 100percent in and making sure our preparation is right.
"We are going to have to see what happens if we beat Bristol because of our position in the league – we have to know who we are playing, whether it’s home or away first and then the gaffer can start planning but at the moment all we know are certain dates that we might be playing but we can’t look forward to it until then."