ATK lost 1-2 to Kerala Blasters in Kochi on the very first day of ISL Season 6.
Carl McHugh had put ATK ahead with an absolute stunner in the sixth minute but the hosts, egged on by a vociferous crowd, hit back with two goals from new signing Bartholomew Ogbeche in the first half itself.
This is the second time that Kerala beat ATK in the ISL opener after having won 2-0 in Kolkata last season.
Under coach Antonio Lopez Habas, who is back at the club for a second stint, ATK are looking to get back to where they were under the Spaniard.
Under Habas, then Atletico de Kolkata won the inaugural title in 2014 and made the last-four the following year.
Former Spanish international goalkeeper Jose Molina then took over the reins in the third season and the Kolkata franchise put up a dominant display to win their second title a record they jointly hold with Chennaiyin FC in the five-year-old history of the league.
But since ATK severed ties with Atletico Madrid who looked after the technical affairs, their performances deteriorated sharply as they finished ninth and sixth in the last two editions.
On Sunday against Kerala, ATK spurned a hatful of chances to score and Habas rued their missed opportunities after the game.
"We did not convert nearly 6-7 chances which should have been converted. The penalty (Kerala's) was unfair on us. We had a penalty call before that, but the referee missed it," the Spaniard had said.
ATK's star player this time is Fijian captain Roy Krishna who was the top scorer in the A-League last season, and the city outfit would hope he fires on Friday in front of the home crowd.
Coming to ATK's rivals, Hyderabad FC are a new addition to the ISL and have replaced FC Pune City who have shut shop.
The team, co-owned by Vijay Madduri and Varun Tripuraneni, will be the latest entrant to the Indian Super League (Hero ISL) roster.
The team will be the first ISL club from Hyderabad a city which boasts a rich footballing heritage and was considered the nucleus of Indian football back in the 50s and 60s.
Hyderabad FC are still to open their campaign and will take on ATK in their first game since inception.
The team has the likes of India centre-back Adil Khan and midfielder Nikhil Poojary in their ranks besides proven ISL foreign stars like Nestor Jesus Benitez, Marcelo Pereira and Marko Stankovic.
Besides, there are youngsters to look out for, like Sahil Tavora and Deependra Negi.
( With inputs from IANS )