Bournemouth came from 2-0 down to win 3-2 in the final nine minutes thanks to goals from Antoine Semenyo, Luis Sinisterra and Lewis Cook.
Iraola later told the Daily Echo: “Obviously it's a very important win for us.
“I think has been the worst game we've played from the four games we played this season.
“I think we were the best team in the previous three and I think Everton has been the best team today.
“I think most of the game we've played more the game Everton wanted to play than our game and I have to accept that.
“I think they deserve to win today.”
On the fight-back, he continued: “One, the spirit. This team has a spirit they always keep believing.
“I think we finished physically very, very strong, considering we played two days ago against West Ham away, a very demanding game.
“I think we have to give credit to the players.
“Also we have the experience from previous comebacks and you can feel it when probably you need this first spark of scoring the first one.
“Everyone started to, (say) hey, we can do it because we've done it previously.
“And I think the ones that came as subs gave us that energy. But also Antoine (Semenyo), I think he won a couple of duels here defending.
“Even Lewis Cook scoring the second one from his position.
“First goal that I've seen him score, really, and also scoring the 2-2.
“The feeling of going quickly for the ball because we were feeling that the momentum of the game has changed and now things are happening in their box and not in ours.
“I think it's great for the players.”