The Cherries were superb as Dango Outtara struck a hat-trick on the day.
Iraola said: “I think it's a great result. Considering especially who we had in front of us, I think it's a very good performance.
“For me, the key of the game probably was to score first, because it's a team that they've basically been winning all the games from the first half, so the game becomes more difficult.
“And I think to be ahead and to make them change a little bit their approach. I think it was key.”
On Ouattara, Iraola said: “Very happy for him, because he's someone that obviously has helped us, as a left back, has played right winger, left winger.
“Now he's playing as number nine, playing very well, adding also numbers. That is always a good extra to have, and I'm very happy for him.”