Defending champions Atletico de Kolkata have become the first team to seal a semifinal berth in the on-going Indian Super League football tournament. At the Vivekananda Yuva Bharati Krirangan in Kolkata today, ATK routed Pune 4-1. Iain Hume struck his second hat-trick of the season. The former Canadian International, who had scored a hat-trick in Mumbai, did an encore with his stunning goals in the ninth, 47th and 83nd minutes before Adrian Mutu (86th) pulled one back for the visitors. Substitute Dejan Lekic, who was brought in place of Sameehg Doutie, sealed the issue with his goal in the dying minutes (90+4th) for their superb win in front of packed turnout of 48,721. Man of the Match Hume also climbed in the goal-scorers' chart to be second behind Stiven Mendoza (10) of Chennaiyin FC. The Antonio Habas-coached thus sealed their second successive last-four berth of the tournament with 23 points from 13 matches. They will face Mumbai City FC in their concluding league match at home on December 4. FC Pune City (15 from 12 matches), on the other hand, stretched their winless run to seven matches and their chance of progression to semis will now come down to 24.01 per cent, as per an ISL statistic.