In Episode 3, tensions escalate as the Blue Lock team prepares for the match against Japan's U-20 team. Captain Oliver Aiku of the U-20 confronts Sae Itoshi with a conflict between their star player Sendou and Sae's aggressive teammate Shidou. Aiku explains that other players might boycott the match if Sendou is excluded. He suggests that Sae proceed without Shidou, which Sae accepts but emphasizes that he will leave the team if they can't keep up with him.

Meanwhile, Isagi reflects on the intense training of the past 15 days and feels calm and focused on the upcoming match. Many spectators are skeptical of Blue Lock and their chances against the U-20 team, especially given the presence of the famous Sae Itoshi.

Ego Jinpachi addresses the Blue Lock players and highlights the importance of the match by introducing the substitute players. The team notices Shidou's absence from the U-20 lineup. Ego urges them to focus on executing their strategy and seizing this opportunity to change their fate.

At the start of the match, Isagi and Bachira launch an aggressive attack, but Aiku intercepts their movement with impressive defensive skills. Isagi recognizes Aiku as a formidable opponent and is determined to overcome this new challenge.

In a lighthearted interlude, Nagi and Yukimiya humorously assess the U-20 players, comparing them to various animals. Rin interrupts them and expresses his disdain for his brother Sae by likening him to an annoying mosquito. The episode ends as both teams stand ready to begin the decisive match, resolved to give their all.