The result also meant Khalid Jamil is still unbeaten in the competition and extended NorthEast's winning run to ten games.
Idrissa Sylla struck in the stoppage-time to help NorthEast United hold ATK Mohun Bagan to a 1-1 draw in the first leg of second semifinal of the Indian Super League here on Saturday.
Antonio Habas was just minutes away from recording his maiden first-leg playoff win in the League when the second-half substitute struck in the fourth minute of injury time to cancel out David Williams' 34th-minute goal.
The result also meant Khalid Jamil is still unbeaten in the competition and extended NorthEast's winning run to ten games.
It was an end-to-end duel, but neither side was able to test the keepers much. It was NorthEast who enjoyed better possession.
However, Bagan scored with their first shot on target and it came soon after the water break.
Roy Krishna got a long ball at the edge of the box. The Fijian flicked it to his strike partner David Williams, who faked a first-time shot sending NEUFC defender Dylan Fox in the wrong direction. He then took a touch before slotting home to give ATKMB an advantage.
As expected, the Mariners tightened the screws on Highlanders, defending and blocking everything that was thrown at them making it difficult for their opponents to score.
NorthEast had a constant supplier in Gallego, who sent quality deliveries into the box from set-pieces but his teammates couldn't find a finish.
Finally in the fourth minute of extra time, the NorthEast camp had a goal to celebrate, thanks to Sylla who made his presence felt with a late equaliser, nodding in Luis Machado's cross.
