Three-time continental champion Pohang Steelers opened the 2012 Asian Champions League group stage with a convincing 3-0 away win over 2008 winners Gamba Osaka on Tuesday.

Kim Tae-su opened the scoring with a 19th-minute header in the Group E match and Zoran Rendulic made it 2-0 for the powerful South Korean club three minutes later when goalkeeper Yosuke Fujigaya’s attempted clearance hit the Serbian defender and deflected into the goals. Veteran Ghana forward Derek Asamoah put the result beyond doubt for Pohang in the 79th minute.

Pohang, Asian club champions in 1997, ’98 and 2009, had to come through a qualifying playoff win over Chonburi of Thailand to reach the group stage, while Gamba qualified automatically by placing third in the J-League.

“We played so badly tonight that I want to apologise to the fans,” said Jose Carlos Serrao, the Brazilian who has replaced Akira Nishino as Gamba coach. “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.”

In Group F, FC Tokyo won 2-0 away at Brisbane and Ulsan held off Beijing Guoan 2-1 at home.

It was a disappointing debut for reigning A-League champion Brisbane Roar, which fell behind Japanese Emperors Cup holder FC Tokyo seconds before halftime when Tatsuya Yazawa scored from Yuhei Tokunaga perfect cross from the right.

Ariajasuru Hasegawa made it 2-0 in the 55th when he knocked in the rebound from Nahya Naotake’s shot in wet and slippery conditions.

At Ulsan, Kim Shin-wook and Ko Seul-ki gave the Korean club a 2-0 halftime lead with goals in the 25th and 35th minutes. Cheng Piao pulled one back for Beijing in the 51st but the Chinese club was unable to find an equaliser in the last 40 minutes.

The opening night of the tournament featured eight matches across groups A, B, E and F. Action in groups C, D, G and H will start Wednesday.

The top two teams in each of the eight groups advance to a knockout round of 16 on May 29 and 30.