Smith had to make do with a place on the bench for the encounter and faced the bleak prospect of coming on for the last 11 minutes with the Hatters trailing by two goals.
“It’s massively disappointing. I thought we dominated the game, missed a couple of good chances, and it’s criminal to give out chances like that when you’re so far in control. To give chances away like that it’s not good enough.
“Today I thought we dominated the game and we haven’t won. But like I said at 1-1 you’ve got to keep it solid, keep it 1-1 and at worst you miss a couple of chances and come off saying at least we got a draw or something.
“We can’t come away losing 3-1. It’s definitely not good enough.
“I wanted to make an impact, to come on and show what I could do. It was so disappointing when the third one went in just as I was about to come on. But obviously you come on and do your best for the team.”
Town were faced with the worst playing surface of the season with the pitch resembling a ploughed field, but the 25-year-old refused to use that as an excuse.
He said: “The pitch is disgusting. It’s like a park pitch, but you’ve got to get on with that.
“We’ve still dominated the game and should have had the win and that’s definitely three points down the drain. I think at worst you come away 1-1.
“You defend what you’ve got, you take 1-1. You miss chances, but to lose 3-1, it’s obviously definitely not good enough.”
On why he had decided not to start Smith on the day, Luton boss Paul Buckle added: “Because we won 3-1 in the last game and I thought (Arnaud) Mendy and (Alex) Lawless were outstanding in the last game.
“So for the integrity of the team and the squad, and Jonathan only trained one day with us yesterday and was on the bench.”