Question about 144 hour transit in Shanghai city

Hi!

I have a question to you about 144 hour transit in Shanghai city.
It is noted, that tourist is allowed to spend 144 transit hours in Shanghai city if he comes from one country, and departs to third.

Can Hong Kong be treated as third country?
So when arriving from USA, staying in Shanghai for 144 hours and then departing to Hong Kong - is allowed without having China visa?