The city masters lost their control over the portal area, and that was indeed quite a severe blow as they lost almost all the formations laid down by William in this region.
As for the Lingerie's masters, they lost a substantial number of them. On top of that, the damage received to the portal was enough to delay the reinforcements, making them feel like they didn't gain any advantage at all by controlling this area.
And as the city masters retreated back to the surface of the underground city, William arrived!
He already was briefed and updated of everything happening here during his travel. He was informed by Sloth's weird scroll of communication. And as they were in the middle of a heated fight, the latter couldn't say more than the update and ended the technique.