The Reds were soundly beaten 3-0 at Camp Nou last Wednesday, with Luis Suarez grabbing the opener against his former employers before Lionel Messi hit a superb brace.
Jurgen Klopp's men are targeting a second successive appearance in the European Cup final, having suffered a heartbreaking loss at the hands of Real Madrid last year, but a huge task awaits at Anfield.
However, Alexander-Arnold has not yet resigned himself to a semi-final exit, expressing his belief in the power of the home crowd ahead of Barca's arrival.
"I think we’ve obviously had decent results this season where we’ve scored more than three goals," the 20-year-old told Liverpool's official website.
"Being at home helps us, we’ll have the fans behind us and there’s still that sense of belief.
"We know it’s going to be really hard, it’s not going to be a walk in the park and everyone has got to be realistic, but we’ve definitely still got that belief within ourselves, in the changing room, that anything is possible, especially at Anfield.
"Hopefully, we will be able to produce one of those special nights here."
Klopp will have to make do without Roberto Firmino and Mohamed Salah against Barca, with the former still recovering from a muscle injury and the latter ruled out after suffering a concussion.
Salah was stretched off during a 3-2 win over Newcastle on Saturday, which ensured Liverpool returned to the top of the Premier League.
Alexander-Arnold is not fazed by the absence of two key stars though, as he added: "Obviously we’ve got two of our main goalscorers out, but it also presents an opportunity for some of the other lads to come in, make a name for themselves and make themselves heroes.
Alexander-Arnold feels Liverpool coped well with the Argentine overall but stressed they cannot afford to be in awe of his ability.
"He is a world-class player, probably the best in the world," he said. "It is going to be a really tough battle, but in fairness to the lads, we kept him quiet for maybe 88 minutes during that game – and he’s produced something really special.
"It just goes to show you’ve got to be concentrated for the whole 90 against him. It’s about having that respect but not too much respect; we can’t be scared of looking silly against him, we’ve got to try and win the ball back as soon as possible and stop him and the other players in that team from hurting us."