KOLKATA: Fresh off a second successive I-League triumph, Gokulam Kerala FC stunned fellow Indian outfit ATK Mohun Bagan 4-2 on its AFC Cup debut at the Salt Lake Stadium here on Wednesday. In a battle between heavyweights from the I-League and the Indian Super League, Gokulam dished out a commanding performance. Slovenian centre-forward Luka Majcen (50’ & 65’) scored a second-half double while P Rishad (57’) and S Jithin (89’) slammed a goal each to clinch three points for Gokulam. ATKMB showed some spark with goals from Pritam Kotal (53’) and Liston Colaco (80’), but its defence crumbled in the second half. The serious injury to centre-back Tiri, who was stretchered off the field in the 40th minute, did not help Mohun Bagan’s cause.