Hugo Ekitike and Cody Gakpo fired Liverpool 2-0 ahead before Antoine Semenyo, after reporting racial abuse coming from a home fan in the first-half, struck twice. However, two late goals from Mohamed Salah and Fede Chiesa saw the Reds win on Friday night.
Iraola told the Daily Echo: “Yes, as you said, really pleased with the performance.
“I think today we've missed a big chance to take something from the game. Probably the game was quite level from both sides.
“I would say that means that we played really well, to play a quite level game against Liverpool.
“The key to take the points obviously is not to concede four goals. I don't think today was a game to concede four goals.
“When the momentum was for our side, we scored (to make it) 2-2.
“At the end it’s a kind of poor goal, to concede the third one, two players going for the first ball, the same ball clearance.
“It's true that Chiesa finishes really well. That's why they are so good, because in moments where they are struggling, they are not having the chances, someone appears.
“In this case it was Chiesa that made a difference.
“And it's a shame. It's a shame because I think it's really proud of a lot of things that we've done. The players have given everything.
“The easiest thing was to give up with the 2-0 because you are playing well and then you find yourself 2-0. But it didn't happen. It's true that we missed the last part and it's a shame.”