The Hong Kong FA champions had taken the lead in the first half and taken it into the break but it was just what the Protectors needed as they came out all guns firing.
Japanese forward Ihata Shotaro fire in the equaliser.
After that, further goals from Frederic Mendy and the Qiu Li gave the Protectors the lead and all the 3 points on offer.
In the other game in the group, Yangon held Chonburi to a 1-1 draw.
Lionel Lewis (GK), Jeremy Chiang (Firdaus Idros), Arai Kenji, Shi Jia Yi (C), John Wilkinson, Shotaro Ihata, Frederic Mendy, Franklin Anzite, Qiu Li (Masrezwan Masturi), Indra Sahdan, Nor Azli Yusof