Andre Schembri broke the deadlock in the second minute of added time, their first goal of the season, to send the home crowd into ecstacy as John Gregory's men thought they had clinched the win.
But a defensive lapse allowed Hyderabad to equalise just a minute later from a corner, sinking the mood in the stadium. Chennaiyin FC, however, had the final say as Schembri this time turned provider to send Nerijus Valskis through on goal with a lovely pass and the Lithuanian did the rest with a composed finish to bring the house down at the Jawaharlal Nehru Stadium in Chennai.
Before the flurry of goals in stoppage time it had been a familiar tale for Chennaiyin - plenty of possession and goal scoring opportunities, but without the proper execution in the final third. They even hit the post twice; Thoi Singh on a 4-on-2 break saw his shot beat the keeper, but hit the upright before Masih Saighani's rasping shot from distance struck the crossbar, both in the second half.
Outside of these chances, Hyderabad keeper Kamaljit Singh also did well to keep out Rafael Crivellaro and Anirudh Thapa.
"When we scored the first goal, it was like 'Did that really go in?'", said Chennaiyin coach John Gregory after the game because of how the game had transpired.
"Chhangte got in some very good positions in the first half but was not able to pick out anybody. We hit the post twice. It looked like we would carry on like that", said Gregory.
He praised the efforts of his forwards saying, "Andre and Valskis are really good finishers. I was shocked that they did not score in the four matches. But they persevered. Andre created that goal himself (first goal). Valskis really did well to set himself up for the goal (second goal). I hope that this is the start of more goals to come."
Gregory was unhappy with the way his side conceded the equaliser, but praised the team for not giving up and getting another goal with hardly any time left and said it was nights like this that captured the magic of football.
"How the hell did we allow them to score when we had taken the lead barely a minute before? But that’s what happens in football. It happens all the time. This is why people go and watch football games. People go to stadiums like this expecting miracles. This is why we still do what we do - for moments like this", expressed Gregory.
He said he was pleased for the players more than anything.
"I’m pleased for the players. I am close to most of them. Our win wasn’t perfect. It was frustrating in attack. We deserved the victory without any question but I wish it was a bit more comfortable."
He also gave a shout out to the team's owner Vita Dani, who Gregory said was 'the best boss in the ISL', for the support from her side despite the tough times.
"I feel pleased for Vita because she’s the big boss and she without any question is the best boss in the ISL. She has been tremendously supportive of me and the players during this tough period."
Chennaiyin FC have a quick turnaround before their next game, at home once more, against Odisha FC on November 28.