The 21-year-old forward returned to Anfield in the summer after loan spells with Stoke City, Birmingham City and Hull City, believing the time was right to establish himself at the club he has supported since childhood.
Koumas arrived with plenty of confidence after helping Hull win promotion to the Premier League through the Championship play-offs. He also enjoyed a memorable international breakthrough, scoring his first senior goal for Wales with a stoppage-time equaliser against Ghana.
The appointment of Iraola shortly afterwards gave him fresh motivation. Having studied the Spaniard's approach, Koumas believed his energetic playing style and work ethic matched what the new Liverpool boss wanted from his players.
"I felt like it could be a massive opportunity for me," Koumas told Liverpool's official website. "The type of player he looks for to help his team is sort of my identity as a player, so I saw it as a real opportunity to come in and try to grab it."
Determined to impress, Koumas joined the Under-21s for pre-season training, knowing Iraola would be watching. His commitment paid off when he was included in Liverpool's travelling squad for their tour of the United States.
"We knew that the gaffer was going to be there having a watch so I just made sure that there was no-one else out there working harder than me," he explained. "There was going to be no-one else showing that they want to play for him more than I was."
Koumas has since made 14 appearances this season and is enjoying the opportunity to work under Iraola, whose demanding approach has made a strong impression on the young forward.
"Playing for him is really special - really, really special. You want to be out there on the pitch fighting for him because he fights for you," Koumas said. "It's an unbelievable privilege to be playing for him."
Training alongside Liverpool's established stars has also helped his development, with captain Virgil van Dijk providing valuable advice. Koumas recalled how the Dutch defender encouraged him before the meeting with Manchester City at Anfield, telling him: "This is where you want to be so let's go and see how you can do in this sort of situation."
One of his standout moments came when he scored on his first Champions League start in Liverpool's victory away to LASK. Having previously scored on his senior debut against Southampton in the FA Cup in February 2024, the goal represented another important milestone. "It was just unbelievable, Champions League night away and I put the ball in the back of the net," he said.
Born on the Wirral and a Liverpool supporter since childhood, Koumas is determined to repay the club's faith and become part of its future success. He insists his ambitions extend beyond securing a regular place in the team, with major trophies firmly in his sights.
"I always want to be in the Liverpool shirt," he said. "But it's time for us now to start winning titles again - league titles, European titles."