AFC Bournemouth head to the London Stadium on Saturday for the late kick off in the capital, where they will face an in-form Hammers who are fighting for survival in the Premier League.
Nuno’s side have lost once in their past five league games, to Chelsea at Stamford Bridge, as they look to haul themselves out of the relegation zone.
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But the Cherries are also on form and are unbeaten in six games.
If they are to continue that run, though, Iraola said his side must be prepared to face a number of different tactical approaches at the London Stadium.
Asked about the Hammers’ extra-time win over Burton Albion in the cup, and if he had placed much focus on analysis of that match compared to the league game, Iraola said he had.
Andoni Iraola. (Image: Richard Crease)
He said: “I've been looking at the game because with West Ham, tactically it's not an easy game because they've got probably the best results playing almost 4-4-2 or 4-2-4 almost, because they play with four players up front with two strikers, with especially introducing Taty and Pablo that they've signed now.
“They've gone against United more classical or more what they used to do, like 4-2-3-1, 4-3-3 with three in the middle.
“And then in the cup they've gone 3-4-3 and there is something that they used against us and we didn't expect in that moment in the league game.
“They were playing a back four and then they changed to a back 5 against us. So now playing in the cup it opens also the option for them because also they recover Todibo, they have Disasi and Mavropanos playing very well.
“So now we have to be ready to face a back four with two strikers, face a back four with three in the middle, face a back five.
“And I think it's a reference for us also, even if it's not the same players because there were not a lot of the starting XI players, but situations that we should have in our head, I think.”
Iraola is looking for a better first half from his team than that at Everton, where they trailed 1-0 at the interval following a flat first 45 minutes.
“I think we need to be better if we want to win tomorrow,” he said.
“We need to start stronger. We need to be more proactive, more go for the game straight away.
“I was a little bit disappointed of how the first half went because we were not a bad first half but passive.
“Nothing was really happening in the game and this is not good for us. We need more things to happen and I hope tomorrow we can, can play better.”