China will not come to blows with the US. IF they did, we would instantly nullify our debt with them and stop all trade. Other nations would quickly snag that trade, forever harming China.
The US cannot help but win, unless it goes nuclear. In which case there really are no winners.
That's true, those debt and trade stoppage would hurt China considerably, in normal circumstances.
But if China goes all out against the US, that'd be almost another world war situation, and trade, debt, GDP growth, economy indicator, all goes out the door. The only thing matters is how much manufacturing capability the country and its allies has, and the natural resource controlled. And of course, there is always this nuclear weapon as the last resort.
China could form an alliance with nearby Islamic nations, Pakistan, Iran that are anti-US. They can start conquering near by countries, Korea, Japan, India, Vietnam. US would have hard time defending those allies due to proximity and supply line, and on land war, China could have advantage with sheer number. If they control the Asia continent, ally with Islamic nations and possibly Russia, and hold their position, use the resources including huge amount of oil reserve, utilize their manufacturing capability and know how, it'd be hard for the US and allies to break.
Just saying....