Heckingbottom told BBC Radio Sheffield: "We tried to stress that Thursday had gone and it was important to focus on this game in terms of application, momentum and getting their minds right in what was another big game.
"We were a little bit sluggish at times, especially first half, but again it shows if your mind's right, you're okay as we got stronger as the game went on.
"It's been a hectic week, but to be honest it's probably better that way because you get everything over and done with in a few days. We've managed to get the result which is great so now we just move forwards and carry on as normal."
Barnsley sit in 10th place in the League One standings, five points adrift of the playoffs.