The Cherries equalized through a brilliant Justin Kluivert strike after Joao Pedro’s early penalty had put Brighton ahead.
However, substitute Danny Welbeck sealed the win for the Seagulls, finding the net via the post with 15 minutes remaining.
Iraola told the Daily Echo: “I think especially second half, we've been a very good team.
“Definitely we've had more clear chances than the goal we scored from Justin. I think the key of the game is one big chance we have with 1-1, we had the momentum.
“I think there is a big save. Then Alex and Dango arrived there with a rebound. We don't find a way to put it inside the net.
“And then in very few moments, we received the second goal. Probably my biggest regret is how we defended the second goal.
“We've had with I think with Rutter and Welbeck, our recovery runs could have been better, we could have defended better the second goal.”
“I think we played as good, if not better than Brighton, probably when we analyse the game, we will have, the things that now, they don't matter, we have more corners, more shots, more crosses, more time in their half,” he said.
“But at the end, when you lose, you have to make these things count and I think they've been better in the two boxes at the end. This is what counts in football.
“I'm quite pleased, I think it has been a good game of football from both good teams, but obviously when you lose, this is the least important thing.”