Frankly speaking, making it through the Open Colosseum was an easy task for those who were not aiming for high scores. As long as the player had appropriate equipment, reached the appropriate levels, and possessed the skill to 'grind' down their enemies, surviving for an hour was an easy task.
Jiaojiao was one of those players who excelled in grinding down their enemies. Being a Dark Paladin who possessed the super-powerful HP recovery ability, Mortal Strike, she did not even bother with killing the monsterlings. All she did was run, and whenever her HP was low, she would just use Mortal Strike to recover it. With that, she had easily lasted through the entire hour.
While Jiaojiao claimed that she was the first to achieve the feat within the server, it was not actually the case. Her misunderstanding was caused by a minor bug within the game.