Second selection: Rivalry Battle （セカンドセレクション「ライバルバトル」）is the second selection of the Blue Lock Project.
25 strikers from each of the 5 strata are left from the first selection. The second selection is divided into 5 stages. It's a leveling system in which strikers are only allowed to move on after they clear each stage. Those who clear this selection will participate in a strengthening training camp with players from all around the world. The first stage is an individual match between a striker and BLUE LOCK MAN, a holographic goalkeeper. Strikers must score 100 goals within 90 minutes to pass within a limited area. After 30 goals, the difficulty increases as more holograms that are stationary are added. After 60 goals, the additional holograms begin moving quickly and the balls that are sent are faster and spinning. The third stage is a match between teams of 3. The team that scores 5 goals first wins. The winning team takes one member from the losing team and continue on to the fourth stage and face a team of four and so on. The losing team is sent to the second stage where they face a team of two. The winning team takes one member from the losing team and the other member is expelled. This process continues until one team has five members. The team that creates a team of five and reaches the fifth stage will have cleared the second selection.
|Stage||Team White||Team Red||Result|
|2nd||Isagi and Nagi (W)||Baro and Naruhaya (L)||5 - 4 (Baro joins the other team)|
|Shidou, Igarashi||Reo, Kunigami||ongoing|
|3rd||Isagi, Bachira, Nagi (L)||Rin Itoshi, Jyubei Aryu, Aoshi Tokimitsu (W)||2 - 5 (Bachira joins the other team)|
|Unknown members (W)||Naruhaya, Baro, Nishioka (L)||5 - 4 (Nishioka joins the other team)|
|Isagi, Nagi, Baro (W)||Kunigami, Chigiri, Reo (L)||5 - 4 (Chigiri joins the other team)|
|4th||Isagi, Nagi, Baro, Chigiri (L)||Rin, Jyubei, Tokimitsu, Bachira (W)||4 - 5 (Isagi joins the other team)|