Kozhikode, April 15 : Indian Super League champions ATK Mohun Bagan were left thoroughly embarrassed at the EMS Corporation Stadium on Friday night when they crashed out of the Super Cup. Faced with a must-win situation against Jamshedpur FC in the crucial Group C match, Kolkata's green and maroon side went down 0-3 - one of their worst defeats in recent times. While the win took Jamshedpur to the semi-finals, ATK Mohun Bagan were left to lick their wounds. On the other hand, in the true sense, Jamshedpur FC had a field day in Kozhikode. Once they took the lead in the 22nd minute, there was no looking back for Aidy Boothroyd's boys. The ATK Mohun Bagan defence made the cardinal mistake of leaving Boris Singh Thangjam without a marker and paid heavily for it. When a cross from the left after a combined move between Ritwik Das and Rafael Crivellaro nearly went abegging in front of the ATK Mohun Bagan goalmouth, an unmarked Boris appeared from nowhere to slam the ball home before running to the sidelines to celebrate the goal by sitting still like a man in deep prayer. Crivellaro continued to cause trouble for the Mariners' defence and nearly scored his second free-kick goal of the tournament in the 26th minute. Unfortunately, his fine effort hit the woodwork. The ATK Mohun Bagan defenders didn't learn from the mistakes they committed early in the match. In the 43rd minute, they made an identical error and allowed Boris Singh Thangjam to score again. The 23-year-old was once again left unmarked by the Mariners' defence inside the box. An oncoming Ritwik Das passed the ball to him and Boris sprinted towards the goal to latch it in and make it 2-0. In the second half, the game turned somewhat physical when both teams often used unfair means. The referee had to brandish the yellow card on one too many occasions. In the 67th minute, Dimitrios Petratos had a chance to put ATK Mohun Bagan back into the game. But the Australian stalwart's free-kick missed the target. To put the game to bed, Jamshedpur further extended their lead late in the fifth minute of stoppage time as substitute Harry Sawyer took advantage of a loose ball inside the box and drove it home to make it 3-0. /IANS