Carlton Morris struck on 90 minutes for the 2-1 Hatters win.
Iraola said: "It's a hard one. It's happened in the opposite way for us, we've won games in the last minute. We should have been more ruthless in the first half.
Advertisement
Advertisement
"The wind was key. It was in our favour in the first half. We had chances. The second half we couldn't play like that because of the wind. They pushed and in the end they won the game.
"It (wind) affected the game. It was very good for us in the first half and very bad in the second half. We were feeling comfortable but not realising (the difference of the) second half against the wind.
"The subs didn't give us the spark they have in other games.
"We weren't finding the spaces with the long balls like in the first half."