Ichigo Kurosaki vs. Grimmjow Jaegerjaquez

 is the first battle between Substitute Shinigami Ichigo Kurosaki and Sexta Espada Grimmjow Jaegerjaquez. This fight proved the difference between a common Arrancar and the most powerful of their kind, the Espada.

Prelude
After Rukia Kuchiki, coming to Ichigo's aid, kills Grimmjow's Fracción, Di Roy Rinker, they are both confronted by Grimmjow, who introduces himself as the 6th Arrancar. Approaching them, Grimmjow asks who is stronger. As Rukia yells to Ichigo to get back, Grimmjow, impaling her with his hand, states it is definitely not her. Enraged, Ichigo attacks Grimmjow.

Battle
As Ichigo strikes, Grimmjow, effortlessly blocking the blade with his hand, pushes Ichigo away. Deciding to toy with Ichigo, Grimmjow goads him to release his Bankai and attack him. After Grimmjow threatens to do to Ichigo what he did to Rukia, Ichigo releases his Bankai.

As Ichigo moves to attack, Grimmjow, stepping out of the way, grabs Ichigo's sword with his bare hand. Using it as leverage to throw Ichigo a great distance, Grimmjow follows up, but Ichigo appears behind him, much to the Espada's surprise. Countering Ichigo's attack by blocking it with his forearm, he kicks Ichigo's head multiple times, sending him crashing into the buildings below. Stating he is unimpressed with Ichigo's Bankai, he notes it only enhances his speed. As the smoke clears, Ichigo, having recovered, fires a Getsuga Tenshō. Though Grimmjow blocks it, it still lands a direct hit, greatly scarring his torso. Rather than being enraged, Grimmjow is surprised and delighted at the technique.

Laughing, Grimmjow notes this turn of events is great because he now finds Ichigo worth killing. Taking out his Zanpakutō, Grimmjow states Ichigo should not just stand there, for now it is his turn. Before Grimmjow can act, he is stopped by the arrival of Kaname Tōsen, who orders him to sheathe his sword. When Grimmjow becomes enraged at Tōsen being there, Tōsen explains he has attacked the Human World with out permission, mobilized five Arrancar and led them to their deaths. Stating all of this being against orders has made Sōsuke Aizen furious, Tōsen tells him his punishment will be decided in Hueco Mundo. Tōsen opens a Garganta, and the two leave, despite Grimmjow being unwilling to go. When Ichigo tells him to come back, as their fight is not over yet, Grimmjow states he is a fool, as he is only alive because the fight is not over. He notes Ichigo's Getsuga Tenshō is damaging his own body, and its use is limited. He states even if he could continuously use the technique, it is still not powerful enough to defeat his released state. His parting words are for Ichigo to remember his name and pray he never hears it again, for if he does, it will be the last thing he hears.

Aftermath
When Lieutenant Renji Abarai, coming over to Ichigo, states he won, Ichigo, claiming he lost, realizes the threat the Arrancar represent and the power level necessary to defeat them - a power level which he does not currently possess. Realizing he is going to have to take drastic measures in order to get stronger to protect his friends and his home, he decides to go and ask for help from the Visored.

When Aizen refuses to punish Grimmjow, Tōsen, grabbing him, asks Aizen to allow him to execute Grimmjow. When Grimmjow notes he must have a personal problem with him, Tōsen, explaining how he serves justice and does not tolerate those who sow discord, severs and incinerates Grimmjow's left arm. Enraged, Grimmjow, moving to attack him, is told to stop by Aizen, who tells him if he were to attack Tōsen, he would have no reason to pardon him. Realizing his situation, Grimmjow reluctantly leaves. The act of losing his arm results in Grimmjow's loss of his position as the 6th Espada.