Obviously the one who stopped the Devil King from escaping was Ariana. She was always waiting in a nearby space crack for this exact purpose. When she found that the Devil King was able to find a path of escape and he was soon going to run away, she used her unique ability to weave strings out of the time and space. Then she used those strings to bind the Devil King.
As she was overwhelmingly stronger than him, the Devil King was unable to even move. Obviously she didn't just let him stay in one place and let the Supreme Goddesses hit him as much as they wanted as that would not help the Supreme Goddesses in getting some training done.
When the Supreme Goddesses had already blocked the escape route and was once again getting ready to fight, she released the binding on the Devil King.
