The Sky Blues now sit third on the Group H table on two points from three games, trailing both Suwon Bluewings and Kashima by three points, with a trio of away fixtures to come.
In front of just over 7,000 fans at the Sydney Football Stadium, Vitezslav Lavicka’s undermanned line-up conceded twice in the second half as they lost for the first time at home in the Asian competition.
Takuya Nozawa struck first just prior to the break before Fellype Gabriel made it 2-0 seven minutes into the second term. Shinzoh Kohrogi added a third in injury time, putting a dampener on Sydney’s hopes of progressing to the knockout stages whilst strengthening their own.
Sydney next take on Chinese club Shanghai Shenhua at Hongkou Stadium on April 19 and desperately need a win if they are any chance of reaching the Round of 16.