Holders Guangzhou Evergrande Taobao are still without a win in the AFC Champions League after suffering a 2-1 defeat to Sydney on Wednesday.
Luiz Felipe Scolari's men - fresh off having beaten Jiangsu Suning 2-0 in the Chinese Super Cup - followed up in their 0-0 draw with Pohang Steelers in the opening game of the title defence with another disappointing result in the Group H encounter at Allianz Stadium.
Robert Stambolziev met Shane Smeltz's header with a volley into the bottom-right corner to open the scoring after 17 minutes before Ricardo Goulart saw a tame penalty saved at the other end five minutes later after Sebastian Ryall had brought down Paulinho.
Huang Bowen atoned for Goulart's miss in the 25th minute by finishing off a well-worked attacking move. However, Sydney sealed the points two minutes from time as Milos Dimitrijevic's shot proved too hot for Zeng Cheng to handle.
The other game in Group H saw Pohang go top with a 1-0 win over Urawa Reds, Son Jun-ho's 20th-minute penalty settling the clash despite the midfielder later being sent off.
Goals from Elkeson and Wu Lei helped Sven-Goran Eriksson's Shanghai SIPG to a 2-1 win over Suwon Bluewings, while Gamba Osaka drew 1-1 with Melbourne Victory.
In Group D, Nasaf beat Al Ahli 2-1 and 2003 champions Al Ain were defeated by the same scoreline by El Jaish, whose victory made it two wins from two for the Qatari side.
Tractor Sazi also have six points to their name at the top of Group C following a 1-0 triumph at Al Jazira and Al Hilal eased to a 4-1 win over Pakhtakor thanks in part to a double from Khalid Al Kabi.