JEF United Ichihara Chiba
The club also went on to win the A3 Champions Cup in 2006, which they participated as K-League champions. Although they lost their first match in the competition against JEF United Ichihara Chiba 2–3, they beat Dalian Shide 4–0 and Gamba Osaka 6–0 to clinch the trophy. Lee Chun-soo became the competition's top scorer, scoring 6 goals in 3 matches. They repeated the merciless attacks in the AFC Champions League that season, beating Al-Shabab 6–0 in the first leg of the quarter-finals. These overwhelming attacks they showed in the season gave Ulsan the nickname "Gangsters of Asia".