Tony Popovic's side became the first Australian side to win the competition last season, but their defence has begun slowly with just one win from their opening four matches.
Having taken the lead through Kerem Bulut after 12 minutes at Pirtek Stadium, Wanderers looked on course to claim all three points, however Ko Yo-han levelled things up with a close-range finish with 18 minutes to go.
The draw was enough to keep Wanderers in second place in the group, however Seoul are right on their heels with only goal difference separating them.
Guanzhou Evergrande lead the way in Group H but failed to extend their advantage after Hiroyuki Takasaki struck in stoppage time to give Kashima Antlers a 2-1 victory.
Substitute Kotaro Omori blew Group F wide open with an 87th-minute winner for Gamba Osaka against Buriram United, the forward sealing a 2-1 win that moves them three points behind their opponents.
Meanwhile, Seongnam moved level with Buriram at the top after a goalless draw with Guangzhou R and F.
United Arab Emirates' Al Ahli closed the gap on their Saudi Arabian namesakes in Group D after Everton Ribeiro netted the only goal in their 1-0 win over Nasaf.
The gap at the top of the group is now just three points after an Omar Al Somah double rescued a point for Saudia Arabia's Al Ahli on their trip to Tractor Sazi, the striker bagging his second in the final minute to earn a 2-2 draw.
Naft Tehran went top of Group B with a 3-0 win at Al Shabab, who remain winless in the competition.
After a goalless first half, the Iranian team surged impressively towards the points thanks to goals from Vahid Amiri, Amir Motahhari and Reza Aliyari.
Ali Reza Mansourian’s side replace Al Ain at the summit after he UAE outfit shared a 1-1 draw with Pakhtakor.
Last season's semi-finalists led after 20 minutes through Jires Kembo-Ekoko but Uzbekistan striker Igor Sergeev ensured a share of the spoils in first-half stoppage time.
