Barcola had made an underwhelming start to his Liverpool career after a reported £123 million move from Paris Saint-Germain, but exploded into life against the Austrian champions in a 6-3 win for Iraola's men on Wednesday.
"Football is like this. You win a game, you are incredible; you have a bad performance, you are a disaster," said Iraola at his pre-match press conference ahead of Saturday's trip to Brentford.
"It is going to be like this for Bradley, for everyone who works in football. We have to assume this."
Barcola's adaptation to a new league and teammates has not been helped by injury troubles forcing Iraola into constant changes.
Cody Gakpo, Alexander Isak and Dominik Szoboszlai have missed the last two matches with injuries picked up on international duty. All three are doubtful for Saturday's trip to Brentford.
"Now it is a matter of finding the best condition and best connection with teammates, the level of understanding, the work of everyone, when to attack the spaces," Iraola added on Barcola's adaptation.
"The more he plays with us, the more he plays with his teammates, the better he will become."
Iraola also revealed that centre-back Giovanni Leoni's return from a long-term knee injury has been further delayed.
The Italian suffered an anterior cruciate ligament (ACL) injury on his debut for the club in September last year.
"Talking to the medical department, it wasn't just an ACL. It was a bad injury; a lot of things around the knee were involved apart from the ACL," said Iraola.
"The plan now is that he starts in the next (international) break. It's not that far off, but a little bit later than we expected."
English Premier League
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