Povetkin started well connecting with Joshua, Joshua began to read how Povetkin was punching with those big hooks and nullified those attempts with a solid defence that kept seeing Povetkin miss. As the fight went on Joshua was in control, started to outbox Povetkin and then finished him. Had he not of got the KO he'd of carried on outboxing him.
Joshua is vulnerable to being hit in the early stages of a fight to anyone looking for a KO, but he will work out how they punch even if that means taking a few and then either counter or just make them miss and then dictate to them. He's still young and gaining experience, a phenomenal athlete to achieve what he has considering his boxing history is a lot shorter than others.
Anglo view or not it was a deserved win and Joshua's quality was clearly beginning to control the fight.