Daryl Dike’s double had given the Tykes a 2-0 advantage with an hour gone.
He then missed a penalty in the 82nd minute and Luton went straight up the other end to pull a goal back through James Collins.
The visitors only just held on in a frantic finale, and Ismael said: “I can just say congratulations to the guys.
“We are proud of the guys for their commitment. They are dedicated to our task and this is the most important thing.
“We have to keep that mentality in the last six games to push to give everything we have. We don’t want to have any regret, as we have a big desire to stay where we are.
“It was a forceful performance, our opponents changed their shape, we were under control until the penalty and after the penalty it was another game.
“This is the Championship and you have to deal with it, to fight, but we got the three points and this is the most important thing. It was important to show a reaction after the loss against Sheffield (Wednesday) and the draw against Reading.
“We have 68 points which puts us in great position, now six games left. Stay focused, recover and onto the next game.”
The opening exchanges saw Kiernan Dewsbury-Hall volley straight at goalkeeper Brad Collins, before Tykes forward Callum Brittain was denied by Simon Sluga.
However, with 27 minutes gone, Barnsley moved in front when Dike collected Cauley Woodrow’s through-ball, shrugged off Matty Pearson and found the corner.
The visitors made it 2-0 when Woodrow’s shot was spilled by Sluga and Dike reacted quickest to notch his second.
Luton substitute Harry Cornick missed a good chance for the Hatters, before the late excitement, while Town almost snatched a point, with Dewsbury-Hall and Pelly-Ruddock Mpanzu blazing off target.
A frustrated Nathan Jones added: “I’ve had to make a few changes at half-time in a lot of games and whether that’s because I’ve got it tactically wrong or what I thought I was going to get from players I didn’t get, so I have to keep making the right decisions and I have to evaluate my decisions. But I wasn’t happy with what we got in the first half and we could have made a number of changes but we didn’t and we were slightly better second half. The (second) goal’s a terrible goal to give away, it was out of absolutely nothing. We didn’t defend it well enough, it’s come back off the goalkeeper, didn’t react, so many things, but they’re on the front foot and we’re not and that was pretty much the story for the majority of the game. We made changes and we were much better second half.”
Luton Town: Sluga, Clark, Pearson, Naismith, Cranie (LuaLua 70), Tunnicliffe (Berry 78), Rea (Bradley 46), Dewsbury-Hall, Mpanzu, Nombe (Cornick 46),Adebayo (Collins 70). Unused substitutes: Moncur, Bree, Morrell, Isted.
Barnsley: Collins, Sibbick, Helik, Andersen, Brittain, Palmer (Halme 57), Mowatt, Styles, Adeboyejo (Morris 57), Woodrow (Frieser 77), Dike. Unused substitutes: Walton, J Williams, Chaplin, Oduor, Sollbauer, Moon.
Referee: Matthew Donohue (Lancashire).
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