It was Mumbai City who started the game on the front foot and were dominant on the ball, and the Islanders had the first opportunity of the game in the 13th minute. However, Ahmed Jahou's long-range attempt was deflected for a corner.
Mumbai continued their dominance on the ball, and they had another opportunity to open the cards in the 23rd minute when, after a poor Northeast United clearance, Rowlin Borges fired a shot towards the goal, but it only managed to hit the side netting.
20 minutes later Mumbai City were dealt a huge blow as referee sent off Ahmed Jahou for a dangerous tackle on Camara. That reduced Sergio Lobera's side to 10 men on the pitch, and thereafter, Northeast United managed to grow in to the game as they made use of the numerical advantage on the ground.
It was all square at the break, but the deadlock was broken just four minutes after the restart. Appiah sent Amrinder Singh the wrong way from the spot after Northeast United had been awarded a penalty for a handball by Borges.
Mumbai pushed for an equaliser, and they came close to getting that in the 67th minute, but Sarthak Golui's header from a corner just missed the target.
Farukh Choudhary had a chance to equalise in the 83rd minute, but the 24-year-old's shot from inside the box was brilliantly thwarted by defender Dylan Fox, who was solid throughout the match.
In the end, it was a deserved victory for Northeast United, who restricted Mumbai City to 0 shots on target in the game.