Group H leaders East Bengal (11 points) were on course for a hat-trick of wins as they took a 2-0 lead with goals from Orji Penn (23rd) and Lalrindika Ralte (54th) at the Shah Alam Stadium here.
But the home side made a surprise comeback following East Bengal forward Manandeep Singh's red card in the 78th minute.
Manandeep who was substituted in place of Andrew Barisic, was shown a red card by Hong Kong referee N G Kail Lam, as East Bengal were reduced to 10 players.
East Bengal still have one match left in group H and will take on Vietnamese oufit Sai Gon Xuan Thanh at home on April 30.
But having garnered 11 points, the Trevor Morgan-coached side has made the prequarterfinals cut.
East Bengal last qualified for the AFC Cup knockouts under Subhas Bhowmick in 2004.