Thor was taken through a tunnel and introduced by the Grandmaster. Thor began to panic when the tunnel ends and was jolted into a meeting with the Elder himself was an eccentric man in colorful clothing, with an assistant beside him.
Thor was reunited with Loki, who revealed that he has been on Sakaar for weeks. Loki became distant from Thor so he could maintain favor with the Grandmaster. Thor was thrown into the slave quarters, where he met two of the slave gladiators, Korg and Miek. Korg introduced himself, and talked to him about the revolution he tried to start, and the Grandmaster's champion. Before the fight, Loki, who is revealed to be using an illusion when Thor throws rocks at him, proposed the idea that he and Thor could rule side by side after he gained enough trust to take control of Sakaar, Thor rejected his offer and was angry at Loki. Towards the end of the discussion, Thor threw a liquor bottle at him to which Korg tried to get rid of him.
Thor was taken by the Grandmaster's followers to have his hair cut for the arena. The Watcher Informant was tasked with cutting Thor's hair before his battle against the Grandmaster's champion. He warned Thor to hold still, and proceeded to cut his hair as Thor loudly shouted.
Loki and the Grandmaster arrived at the Grand Arena to witness the fight. Thor entered the arena, putting on his helmet and picking up his weapons as he prepares to engage his contender, while Valkyrie watched the arena from her ship above.
The Grandmaster introduced Thor, and the audience began to call out for their favorite champion. As the Grandmaster turned to introduce his champion, his call was cut short as the combatant broke into the arena, revealing himself to be the Hulk. Thor was overjoyed at the sight of his former teammate, attempted to talk and negotiate with him, but made the mistake of calling him "Banner".
As he watches, Loki became nervous and uncomfortable after seeing the Hulk, following their last encounter after the Battle of New York. Refusing to acknowledge Thor, despite his attempts to make him calm down, Hulk fought against his former ally, by smashing Thor into the arena wall before he threw his hammer at him, which narrowly misses Thor's head. However, Thor turned the table, grabbing the hammer as Hulk charged at him again and smashed him hard across the arena wall, much to the shock of the Grandmaster.
Thor tried Black Widow's calming technique on the Hulk, but it failed to work. Hulk smashed Thor around; similarly to how he smashed Loki around in Avengers Tower, much to Loki's pleasure, gloated that now he knows how that feels. Frustrated at being unable to reach his former ally, Thor went for the attack, hitting him several times with Hulk's hammer, destroyed Hulk's battle axe in the process; however, this only further angers his opponent. After taking several more hits, Hulk disarmed Thor and send him flying across the arena and repeatedly hit Thor's face into the floor.
Just as it looked like Thor was about to die, he suddenly had a vision of his father, causing his lightning powers to surge, and hits Hulk with a large bolt of lightning, sending him flying through the air. Thor continued to re-gain the upper hand, hitting Hulk with a lightning-powered punch, gaining the support of the spectators and the other gladiators, who were watching from their quarters. However, unwilling to see Hulk lose, the Grandmaster cheated and fixed the fight by activating the Obedience Disk on Thor's neck and incapacitated him. Hulk leaped upward into the air and attacked Thor which left him unconscious.
Thor woke up in Hulk's chamber, where the two former allies had a conversation, and Thor kept pleading for Hulk's assistance, but Hulk refused to acknowledge their friendship, grumpily stated that Thor liked Banner better. He did, however, reveal the location of the Avengers' Quinjet, nearby on Sakaar. Despite Hulk knocking Thor unconscious, Thor insisted that he won the fight; he later recounted their fight to Bruce Banner after eventually forcing Hulk to revert back, saying he won easily, though Banner was not entirely convinced that this is true.