In the opening round of the UEFA Champions League league phase, Liverpool came from behind to beat Atletico Madrid 2-1 at Anfield. Just one day before the match, Mac Allister had publicly stated that he had not received a contract renewal proposal from the club and that he felt very upset; in this game, he scored a decisive world-class strike from outside the penalty area, responding strongly through his performance on the pitch.

In the 17th minute, Llorente opened the scoring for Atletico Madrid. The midfielder has now scored five goals in three away appearances at Anfield, including two goals in Atletico's 2020 Champions League knockout victory over Liverpool. In the 40th minute, Szoboszlai equalized, sending the two teams into halftime level at 1-1. Five minutes after the start of the second half, Mac Allister unleashed a powerful long-range shot from outside the box that flew into the corner, leaving Oblak unable to stop it. Liverpool completed the comeback and secured the win.
After the match, Mac Allister discussed his pre-match comments about his contract: “I tried to honestly express how I felt inside, and it helped me release some of the pressure. Whether I have two more years here, longer, or leave earlier, until my final day here, I will stay true to myself and give everything I have. I really enjoy playing for this club and I am focused on living in the present.”
Mac Allister's current contract runs until 2028, and Liverpool are not under immediate pressure to renew it. Speaking about his long-range goal, he said: “When I find myself in that position, I will try to shoot. Those opportunities do not come around often, but I am happy. I naturally like scoring goals, today's goal was beautiful, and more importantly, it helped the team.”
This match was also the first time manager Iraola had defeated Simeone in all competitions; before this, he had recorded three defeats and one draw against the Argentine coach. Argentina international Alvarez started for Atletico Madrid, and he had been seeking a move away from the club during this summer transfer window. In addition, Liverpool new signing Barcola made his home debut in this match but was substituted after suffering a calf cramp during the game.
Mac Allister is optimistic about the team's prospects: “This team has outstanding talent and a strong desire to win, and we have everything needed to achieve success. But we need to turn our ability into results. If everyone shares the same goal, we can achieve something special.”