A 90th minute header from Ollie Watkins saw Villa draw 2-2 at Dean Court.
Iraola told the Daily Echo: “I think it's a hard one because I think we really deserved the three points today.
“We had the clearest chances. I think their keeper was really, really good. He made the difference today.
“But it's true with the quality of the players we were facing, every small detail, every difference that they can make, like we saw at the end, can make us concede a goal.
“And at the end we finished with a point that before the game probably you think, 'okay, it's a very good point against Villa.'
“They're a very good team. But after how the game went. I think it's not good enough for us."
On Watkins' winner, he added: “I think Zaba (Illia Zabarnyi) was there, was covering between him and the goal.
“Zaba has been amazing, covering one against one with a lot of space, Ollie Watkins all the game.
“But this kind of players they need just 20cm.
“He was facing his goal, and he just scores.
“Sometimes you have to accept that. It's a very good goal. And it was a very good cross and for sure we can defend better.
“But for me the key was more in the other side, the chances we had to score the third one and probably finish it and we didn't it."