Isak set a Premier League transfer record last summer as he completed a £125M move from Newcastle United - who Liverpool face tomorrow.
The Sweden star is on course for a hostile reception back on Tyneside after an injury ravaged first year at Anfield under former manager Arne Slot.
The 26-year-old has played a part in every preseason game since his return this month and Iraola has been impressed.
Isak will be under pressure from the off back at St. James' Park - after the former Real Sociedad hitman scored 54 goals in 86 games for the Magpies - and Iraola is confident that if he stays fit, Liverpool will see the best of him.
"It's a massive season for Alexander. He knows it's about two things: the first is availability, and without availability we cannot have the second thing, which is performance level.
"This has to be the first aim for us, to keep him in a good place in terms of being available. I’m sure if we manage to do this, he will perform well, because he's been very good in preseason.
"If we keep him at a good level he will score goals and be a threat. I have no doubts about his level.
"He's quite a unique No.9 in terms of he can come to receive and be technically very clean, but he's also very good at attacking space."