Unlike Luna, the panther didn't have as much room for maneuverability and was struck by several of the fireballs thrown at him by Luna. Another reason for Luna's increased hit rate was the panther's decreased agility because its endurance had long since taken a hit after it had to take on several opponents in a row, out of which Luna was only the latest and the most dangerous.
Neither Christina nor Sarah had been strong enough to give the panther a run for its money. They had barely managed to hold it back for some time by giving it all they had. But Luna was a different breed. Her attacks hurt the panther like hell and it wanted to evade as much as possible.