FC Tokyo got off to a dream start in their Asian Champions League debut on Tuesday night as the Emperor's Cup holder beat reigning Australian A-League champion Brisbane Roar 2-0 away in their Group F opener.

On a night of contrasting fortunes for Japanese clubs, Gamba Osaka were left to pick up the pieces of a comprehensive 3-0 defeat at home to South Korea's Pohang Steelers.

Tatsuya Yazawa put Tokyo in front in the dying seconds of the first half and Ariajasuru Hasegawa netted a simple second 10 minutes after the break, sealing the Gasmen's first competitive win under new Serbian manager Ranko Popovic.

In a Group E game at Expo Stadium, 2008 ACL champion Gamba fell behind when Kim Tae Su headed in after 19 minutes and a fluke goal put the visitors 2-0 ahead, Gamba goalkeeper Yosuke Fujigaya's punched clearance from a corner hitting Zoran Rendulic and finding its way into the back of the net.

Playing under new coach Jose Carlos Serrao, Gamba's hopes of a comeback ended when Derek Asamoah broke free to bury the third on 76 minutes.

"We played so badly tonight that I want to apologize to the fans," said Serrao. "We had two chances before our opponents took the lead but could not take them. We have a lot to work on if we want to advance past the group stage."