Ahead of Saturday's clash with Arsenal, the Cherries received a major boost after their Brazilian striker's red card received in the draw with Manchester United was overturned.
Iraola said this morning: "For me it's clear that the system is not working very well.
"The process, because it's a play where the ref takes the decision, he sees it live, he decides it’s a foul, yellow card. The VAR with all the replays, different views, corrects the decision, supposedly it has to be clear and obvious.
"After seeing all the replays and putting every image they decide to overturn it, it has big consequences for us. And now other people watching all the reviews, the same replays, the same things they say to overturn that decision that already was overturned.
"And obviously I support the VAR, but it's clear that there are still a lot of things that they should be done much, much better."
"We can't play just our normal game"
Evanilson has seven goals in the past 12 games, but Iraola admits even with his availability, facing Arsenal is a massive test. Iraola insists even if counterpart Mikel Arteta selects a shadow team given their Champions League commitment, the Gunners will still be formidable.
He continued: "Arsenal is going to be very, very, very difficult. They've lost one game this season at home.
"Just one game, West Ham. To beat them, you have to do something special.
"If you play at your level normal, it's not going to be enough. We have to be especially good if we want to beat them, especially away. So we will try to do it, but we know it's going to be very, very difficult because it's a team that is, defensively, they are the best team in the league by far.
"The number of goals they've conceded is ridiculously low and it's difficult to have chances against them because they are very well organised. They suffocate you in a good way and it's difficult to have the chances.
"But also, as you said, they’ve had some draws, they’ve had some results probably not that the ones they wanted. And we will try also to get one."
Unbeaten over April
The Cherries will meet Arsenal unbeaten over the past month, with Iraola declaring their form as "amazing". Their progress gives him confidence going to London tomorrow.
He also said: "I don't think we've lost a game in April, in all the month, we haven't lost a game. You know, okay, it hasn't been amazing, but I think it's four games without a loss in the Premier League. It's very difficult this way.
"It's not easy to be four games (unbeaten). It's true that we draw games and the draws, the one point now doesn't make you the jump you want in this standings but it shows to be four games without a loss also that we are being very competitive and we are there in the games and okay, we don't win because they scored in the 96th or 97th minute and this. But I think the team gave us a good game.
"Now it's a matter of these small details. We are seeing every game late winners, one small thing and two, get to your side.
"Now, I think we have a different kind of games because we are facing Arsenal, Villa, City, especially these three, where we need a little bit more. We just not to be competitive. No, we have to be in one moment or defensively or offensively, brilliant.
"Because otherwise it's not enough against this level of teams. And I hope we can do it tomorrow."