Enemy attack.
In a fight as prolonged and evenly matched as the one Wukong and Marcus were having, any mistake would be fatal. However, one side was just acting instinctively, while the other had to think through every move.
Marcus was using the staff techniques he learned from Wukong and using the advantages of ranged magic that Inna and his master left behind.
In one hand Marcus held a staff, in another a sword. Sometimes he used his space magic to put one away and grab the other with both hands, especially to make better use of the long reach of the staff.
He learned from the constant Wukkong vs. Inna fights they had in training that Wukong at close range was too strong to engage. He had to be cautious and keep his distance.
However it was not easy, the monkey had a thousand tricks. Its hair could take its own shape, it could be armor or armor.