Conor Chaplin had given the Blues a first half lead as they tried to secure their first home win of the season.
But late goals from subs Enes Unal and Dango Ouattara - in the 87th and 95th minute respectively - won the game for Bournemouth.
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"I think it was a game that definitely we didn't deserve to lose," Iraola told the Daily Echo.
“I think we missed, especially first half, clear chances to score and we had at the beginning of the second half also some moments where we were pushing.
“You don't score the goal and probably you start thinking it's not going to be our day today, maybe.
“But I think the subs especially the finishing product of them has been the decisive thing."
Those subs - Ouattara and Unal coming on after 63 minutes for Adam Smith and Justin Kluivert - made the difference.
Bournemouth players celebrate their late winner in SuffolkBournemouth players celebrate their late winner in Suffolk (Image: PA) Iraola enthused: “When they become the protagonist, they finish what we were not finishing before.
“I think we were having the chances especially first half, the post, the very clear chance from Tav (Marcus Tavernier).
“We had, even before the goals, one situation, three against one where we don't decide well and we were kind of arriving quite easy to the last third, but I think Ipswich was defending very well.
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“They were very compact. They were not giving us a lot of chances to cross properly.
“We were arriving but there was a moment in the second half where it was not so clear and I think we needed this fresh energy and fresh mind from the subs.”