Bournemouth were excellent in the first half and took a two-goal lead into the break thanks to a Junior Kroupi brace.
But the hosts fought back and were much the better side in the second period, drawing themselves level.
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The Cherries retook the lead late on, but Palace equalised once again through a stoppage time penalty from Jean-Philippe Mateta, the striker completing his hattrick.
Asked what changed at halftime, and if it was a case of his side underperforming or Palace stepping their level up, Iraola told the Daily Echo: “Both things because they pushed us a lot more.
(Image: Adam Davy/PA Wire)
“First half we were playing a lot in their half. We were having more of the possession. But obviously they are losing 2-0, they have to risk more.
“They put Eddie Nketiah on, they put Ismaila Sarr and Mateta together. And every direct ball, Mateta was winning almost every first ball. And after the second ball it was been difficult with Ismaila Sarr breaking, with Eddie Nketiah, they were arriving more than they were obviously in the first half.
“And we've been suffering and we've been pushed by them. There is a part where they've done very well.
“There is a part where we should have like shown, I don't know, more composure. But I also appreciate that after the 2-2 the momentum is for them.
(Image: Keith Gillard)
“We showed some personality. The third goal I think is very nice. Starting from the back, building up calm. We arrive one side, the other, we score the third goal.
“And I think you could feel the 3-3 coming because they were, every long throw, every free kick, they were putting a lot of bodies. It's a team that from set plays is very dangerous.
“They've shown it but not the way it has been, I'm not happy because if Mateta scores the last one it’s 3-3, you have to accept it’s amazing from them, it's 3-3 but the penalty, no.”