Reigning champions Atlético de Kolkata became the first team to qualify for the semi-finals of Hero Indian Super League 2015. The defending champions rode an Iain Hume hat-trick against FC Pune City to seal their place in the semis. However, things weren’t always easy for the team beset by injuries. Head coach Antonio Habas was dealt his first major blow of the season just 74 minutes into their campaign as marquee player Helder Postiga picked up an injury not to feature again in the league stage. This was a sign of things to come for Kolkata as they saw influential figures such as Josemi and Javi Lara also bid adieu to Season 2 due to injury. Arata Izumi, another talismanic player in the ATK fold, was also sidelined for a significant period on account of injury. These injuries coincided with Kolkata’s leanest period in terms of results where they lost three consecutive matches. The champions though dug deep and put together a run that propelled them into the semis. Here is an in-depth look at Atlético de Kolkata’s journey to the semi-finals where they will play Chennaiyin FC.Vs Chennaiyin FC, October 3: In keeping with Season 1, Atlético de Kolkata took part in the inaugural match of the season and this time they beat the Super Machans 3-2 in Chennai thanks to Helder Postiga’s brace. The victory did, however, come at a cost for Habas’ men who lost Postiga to injury.Vs FC Goa, October 7: Kolkata travelled to FC Goa next in what was a repeat of last year’s semi-finals where Kolkata came out on top in a penalty shootout. The previous three encounters between these two powerhouses of Indian football had ended in draws. And their first encounter this season in Fatorda was no different as Keenan Almeida cancelled out an Arata Izumi strike in the 81st minute to share the spoils.Vs Kerala Blasters FC, October 13: Kolkata’s first home game of the season was a repeat of last year’s final. The last time they had won 1-0 and this time they ran away 2-1 victors. However, both of ATK’s scorers in the game – Arata Izumi and Javi Lara – injured themselves in the match. Izumi returned later but Lara’s injury turned out to be season-ending. The match also marked the 25th goal of the 2015 Hero ISL which was scored by Lara.Vs FC Pune City, October 17: Arguably one of ATK’s most disappointing performances of the season as they fell behind to a Jackichand Singh strike in the second minute and they could not recover from there in Pune. This loss against the Stallions marked the beginning of their leanest patch of the season.Vs NorthEast United on October 23: Atlético suffered their second consecutive defeat by a 1-0 scoreline when they faced the Highlanders in Guwahati. Kolkata put in a much improved performance from their last game but a 77th-minute strike from substitute Nicolas Velez sealed their fate.Vs Delhi Dynamos FC on October 29: Skipper Borja Fernandez led his team out hoping to overturn the recent run of results against his team but the story remained the same. The Lions inflicted a third loss in a row on Kolkata thanks to another late strike from substitute Gustavo dos Santos, leaving ATK fans at the Salt Lake Stadium stunned.Vs Mumbai City FC on November 1: Kolkata headed into the game desperate for a win after plummeting down the table on the back of three losses in a row. Step forward Iain Hume who had failed to score a single goal in his previous six games. The Canadian looked in inspired form as he netted his first hat-trick of his professional career to hand his side a 4-1 win in Navi Mumbai.Vs NorthEast United FC on November 7: The joy of their 4-1 triumph was short-lived, however, as the Highlanders returned to haunt them by doing the double over Kolkata thanks to an early Simao penalty. This home defeat left their semi-final chances dangling by a thread.Vs Kerala Blasters FC, November 10: The turning point of their season came in Kochi as Kolkata re-ignited their campaign with a thrilling 3-2 win over Kerala. Arata Izumi returned from injury and made up for lost time as he bagged a brace, including the winner with the last kick of the game.Vs Delhi Dynamos FC on November 14: A tricky tie considering that Delhi had been unbeaten at home at that time, Kolkata returned from the capital city after a well-deserved draw. It was Iain Hume once again scoring for ATK before Richard Gadze found an equalizer for the Lions.Vs Chennaiyin FC on November 18: In a crunch tie between two teams desperate to keep their semi-final dreams alive, hosts Kolkata came out 2-1 victors over the Super Machans with strikes from two of their most influential players over the course of the season – Sameegh Doutie and Iain Hume.Vs FC Goa on November 22: Kolkata blew away a FC Goa side who came into the game off the back of a 7-0 drubbing of Mumbai City FC. The hosts put four past the Gaurs riding a brace from Sameehg Doutie and strikes from skipper Borja Fernandez and Iain Hume. ATK also registered their first clean sheet of the season in this game.Vs FC Pune City on November 27: After a disappointing showing against the Stallions in their previous encounter, Kolkata set the record straight with a convincing 4-1 home win that saw Iain Hume bag his second hat-trick of the season. The win cemented ATK’s spot in the semis and also saw their newest acquisition Dejan Lekic get his maiden goal.Vs Mumbai City FC on December 4: Having already secured semi-final qualification, Kolkata ended their league campaign on a bit of a damper after Mumbai beat them 3-2 late in stoppage time through Sony Norde’s second goal of the night. Kolkata had rested key individuals such as Ofentse Nato and Amrinder Singh in their home game.