Liverpool went down to 10 men inside half an hour at St. James’ Park when Van Dijk’s challenge on Alexander Isak was deemed to be denying a goalscoring opportunity.
Having been appointed the club’s vice-captain over the summer, Alexander-Arnold was the man to take the armband from Van Dijk following his dismissal.
The 24-year-old endured a volatile start to the game himself as he escaped a second yellow card for a challenge on Anthony Gordon inside five minutes.
He responded positively to the adversity, however, with Klopp conceding that he considered removing his right-back from the situation during the first half.
“I think a lot of people would have thought, and I thought as well for a minute or two, do we have to change him? Do we have to make that change already? And I’m very happy that I didn’t do it,” admitted the boss.
“I think we all agree that everybody in the stadium besides the Liverpool fans wanted him to go off as well in the next situation and I’m pretty sure it would have happened if Trent would have given anybody the chance to do so.”
Alexander-Arnold will captain the side at Anfield for the first time when Aston Villa visit this weekend due to Van Dijk’s absence through suspension.
Klopp described the showing at Newcastle as a “big step in his development” and said that he expects it to be an “honour” for Alexander-Arnold to lead out the side on Sunday.
“That was a big step in his development, absolutely, to keep his calm and even to step up in the game, because he was really in it,” he continued.
“For me it’s difficult to think about myself in that situation [captaincy]. I was captain and it was more work than honour as I remember but probably would be a massive honour for him but thank God he could practice it last week.”