Liverpool were forced to dig deep after falling behind to a familiar foe early in the contest. Marcos Llorente opened the scoring after 17 minutes, taking his remarkable tally to five goals in his past three visits to Merseyside. Dominik Szoboszlai eventually levelled the tie in the 40th minute, paving the way for Mac Allister's heroics.
"Normally when I'm in those positions I like to shoot," Mac Allister stated. "It doesn't happen very often, but I'm happy because I love to score goals. Today, it was a nice goal and was important for the team as well, which is what I want.
"I think we have an amazing team. We have quality, we have desire, and we have everything to be successful. But we need to show it. We have to have everyone in the same page, and we can do great things."
The victory also marked a significant milestone for Liverpool manager Andoni Iraola. He claimed his first-ever managerial win against Diego Simeone, having previously suffered three defeats and one draw against the Argentine coach.