Ah, but I didn't say direct opposition, nor did you in your original post. I thought you meant any form of opposition, which could be direct or oblique, diplomatic or militant, or otherwise. Any support to the claims of ASEAN nations in the South China Sea is an act of opposition to China, as is opposition to the DPRK. The Seventh Fleet as it presently stands is a threat in being to China as well by its existence, and you can certainly expect Xi to have considered that when he called for a new plan to fully modernize the PLA by 2035 and make it capable of fighting worldwide by 2050; while an extension of long-standing trends, the PLA includes the PLAN, and fighting worldwide requires a blue-water navy appropriate to China's growing position abroad. The mere existence of the US support for Taiwan is fully a thumbing of noses at Beijing's claims, and it seems to be one that they're increasingly unwilling to tolerate given the rather pointed remarks that very carefully did not mention the Democratic Progressive Party or its pro-independence positions. Chinese conflicts with Japan over Diaoyu makes any support of Japan a oblique act of opposition to China in the matter due to those two nations being in opposition over the matter and neither side being willing to accept anything less than total victory.
If you had, however, meant direct opposition and direct opposition only by your original post, then I'd have to suggest that oblique forms of opposition do exist. Moreover, not all powers necessarily view opposition in the same way. China, I'm also concerned, is creating opposition where it doesn't need to exist. They, in the narrow-minded pride of young nations (and isn't it a hoot to call China "young"), have been very militant about their myriad border conflicts of late, which naturally drives nations together in opposition: India, Bhutan, Japan, Vietnam, Philippines, Malaysia, Brunei, and amusingly, both Koreas (their position in the DPRK is maintained because they have nowhere else to turn). If China were not so militant over the Paracels, Spratleys, McMahon Line, and Aksai Chin, they could actually make serious headway in developing a strong diplomatic position in Southeast and South Asia if their growing rapport with Laos, Burma/Myanmar, and in Africa are anything to judge by. Unfortunately, their "surrender to us or go against us" policies are forcing many small nations into a position of direct opposition where they do not necessarily wish to be, and if the US happens to suggest that this may be a little unfair to them or that the Nine-Dash Line happens to be a travesty of international maritime law, that is itself another act of opposition to China.
EDIT: Accidentally listed Malaysia twice where I meant Myanmar. >_<