Gamba Osaka of Japan and Guangzhou Evergrande of China booked their places in the quarter-finals of the AFC Champions League Wednesday after the two former Asian champions defeated South Korean sides FC Seoul and Seongnam FC in the Round of 16.

Japanese treble winners Gamba beat Seoul 3-2 at home to complete a comprehensive 6-3 aggregate victory while a brace by Ricardo Goulart saw Chinese champions Guangzhou down Seongnam 2-0 for a 3-2 aggregate triumph.

Those results leave K League Classic champions Jeonbuk Hyundai Motors as the only Korean club in the last eight of the competition after Suwon Samsung FC were eliminated by Japanese side Kashiwa Reysol on Tuesday.

Takashi Usami had scored twice in Gamba's 3-1 victory in Seoul and the forward played a key role in the opening goal for the 2008 champions at Expo '70 Stadium, drawing several defenders before dinking over a cross for Patric to head home after 16 minutes.

Mauricio Molina squandered a glorious chance to get the visitors back into the contest when the Colombian dragged a penalty kick wide three minutes before half-time and that miss would prove even more costly when Gamba struck again in the final minute of the first half through Shu Kurata.

Yun Ju-Tae gave 2013 runners-up Seoul a glimmer of hope when he turned in Shim Je-Hyuk's cross in the 58th minute but substitute Lins put the game to bed by heading in Hiroko Fujiharu's cross four minutes from time.

Yun grabbed his second of the game in stoppage time for the well-beaten Korean side.

At the Tianhe Stadium in Guangzhou, the home side had to come from behind after conceding a late penalty in a 2-1 loss to Seongnam in the first leg.

But the 2013 champions got a spot kick of their own when Huang Bowen's shot struck the elbow of Kwak Hae-Seong and Ricardo Goulart converted the resulting penalty in the 27th minute to level the aggregate score and put his team on top on away goals.

Kim Do-Heon missed a great opportunity to restore Seongnam's advantage just before half-time when his tame shot from the edge of the box was too close to goalkeeper Zeng Cheng.

Goulart would wrap things up in the 57th minute as the Brazilian headed in Zheng Long's corner for his tournament-leading eighth goal to send Guangzhou into the quarter-finals for a fourth consecutive year.