Sun Yu should now by now, clearing is likely to invite IR's bringing the shuttle down, a placement shot, not so much a smash.
I somehow feel that Sun Yu lost to herself in the end ,although IR played very well; Sun Yu just failed to seize her chances and played into IR's hands.
In some instances, instead of Sun Yu attacking hard, she should have disguised it as drop shots to bring IR to the front, and then anticipate her net or lift, making full use of her height advantage, also ever ready to ponce at the net.
Perhaps , switching to a body smash instead might do the trick, rather than smashing into where IR was ready to defend.