Travel to Beijing with onward travel to Macau

Hi
I will be travelling to Beijing direct from the UK in December where we will stay for 3 nights. We intend to use the 144 hour TWOV for our stay in Beijing. From there we fly direct to Macau where we intend to spend another 3 nights before flying to Thailand.
Am I correct in assuming Macau is classed as a third country when departing from China and we would still not require a visa.