Yeah, Hirano Variations from the 4th set on were too much for Chen Xingtong, Tongtong is a bit one dimensional too, Just trying to be consistent and reactionary and waiting for errors without actively looking for attacking chances can be punished severely, She must be very relieved to win this match, this same thing happened in the Japan Open 2018, up 3-0 9-6 in the fourth set against Ito, She let that escape and she couldn't contain Ito serve variations, tricks and 3rd ball attacks from then on.
On the other hand, This is good for Hirano's growth but this is not going to happen eveeytime, She could have been ousted by Liu Weishan early in the tournament, and against players that like to take the initiative and keep being aggressive this won't happen, You can't always wait for you to be down 3-0 before you decide to zero in on the match. It's almost always too late