SUWON (AFP) - Asian football suffered one of its darkest days Wednesday as a showpiece regional semi-final erupted in violence and a major match-fixing scandal was blamed for a tragic apparent suicide. In a blow to attempts to boost Asian soccer, the AFC Champions League semi-final between Suwon Bluewings and Qatar's Al Sadd was temporarily halted as both teams traded punches in an ugly all-in brawl. A tepid encounter at South Korea's Suwon World Cup Stadium exploded late in the second half after Al Sadd's Mamadou Niang raced through for his breakaway second goal while much of Suwon's team were tending to an injured player. A pushing and shoving match sparked by a fan invading the pitch deteriorated into chaotic scenes as players and staff were drawn into fighting which marred one of Asia's biggest club games. Al Sadd's Kader Keita and Suwon player Stevica Ristic were both sent off as order was finally restored and shortly afterwards, goal-scorer Niang became the third player expelled for a second yellow card for kicking the ball away. Boos rang out around the stadium as the match finally ended after 10 minutes of injury time, with Suwon facing an uphill battle against the Qatari team in next week's second leg in Doha. Al Sadd coach Jorge Fossati admitted Niang's second goal was controversial and said the player "lost his head". Hours earlier, former Sangju Sangmu Phoenix coach Lee Soo-Cheol was found hanging in his apartment south of Seoul, weeks after being sentenced in charges related to a fixing scandal that has rocked South Korea's K-League. Lee, 45, was sentenced to two years in prison with three years of probation last month on charges of blackmailing the parents of a player implicated in match rigging to take a bribe. "No suicide note was found, but his family members said he has been distressed in recent months by the match-rigging scandal," an unnamed investigator told Yonhap news agency. In July, prosecutors charged 57 people -- 46 current and former players and 11 criminal gang members and gambling brokers -- for fixing 15 matches last year. Lee's death follows the suicide in May of Jeong Jong-Kwan, a 29-year-old midfielder who killed himself in a Seoul hotel room while being investigated for his involvement in the scandal. It has been a difficult year for Asian football after regional soccer chief Mohamed bin Hammam was banned from the sport for offering bribes to FIFA delegates, an accusation he denies. China's Zhang Jilong has taken charge of the Asian Football Confederation (AFC) as acting president and has pledged to do his best to clear up corruption problems and improve standards. Wednesday's fighting is the second controversy to hit the climactic stages of the AFC Champions League after Al Sadd's quarter-final opponents Sepahan were handed a 3-0 forfeit for fielding an ineligible player.