Sony Norde's 84th minute strike helped Bagan beat Minerva Punjab FC 1-0 and move back to the top of the table after Aizawl's win against Churchill Brothers earlier.
Both Bagan and Aizawl are level on 33 points, and meet each other next week in Mizoram, in a fixture that could potentially decide the title with just two games left to play in the season. This was Bagan's first away win in seven games in the I-League and the most important one with title on the line.
With the game heading towards the goalless draw, Norde hit the home team on the counter. He found space on the left, sprinted ahead and with just the keeper to beat, easily side-footed the ball into the bottom left of Arshdeep Singh, who had a terrific game in front of goal.
Darryl Duffy and Norde had plenty of chances in the game but were left frustrated throughout with a combination of insipid finishing and some resolute defending from Minerva. The win now gives Bagan some breathing space ahead of the trip to Aizawl - where they play after an AFC Cup game just three days prior.
Aizawl free-flowing in important win
Kamo Bayi's brace helped Aizawl FC stay in the hunt for the title with a 3-1 win over Churchill Brothers in Goa on Saturday.
Bayi's scored in the 7th and the 46th minute before Anthony D'Souza pulled one back in the 69th to unsettle Aizawl. The nerves were calmed when Laldanmawia Ralte netted Aizawl's third in the 84th to seal the game and keep Aizawl in contention for their maiden I-League title.
East Bengal, who are also in the hunt with the two teams are now six points behind the leaders with a game in hand and host DSK Shivajians on Sunday.
Both goals by Bayi were well taken and neatly finished. For the first one, he brushed off two Churchill defenders to slot it between the keeper's legs. For the second, he received a sumptuous ball from Brandon Vanlalremdika - who had a fantastic game himself - to chip it over Naveen Kumar.
Churchill brought in two wingers -- Gabriel Fernandes and Anthony D'Souza -- and that helped the home side play better in the attacking half, which led to their first goal. Anthony Wolfe set Anthony D'Souza up with a lovely ball inside the box and the winger side-footed his first-time shot to the bottom left.
With Churchill increasingly on the attack, Aizawl held firm in the fifteen minutes of the match before Laldanmawia's goal. The Mizo's goal was another peach as he curled it above Naveen Kumar from just outside the box.
Shillong Lajong out of title race
Earlier in the day, goals from Sunil Chhetri and Harmanjot Khabra helped Bengaluru FC end Shillong Lajong's title hopes with a 2-0 win at the Jawaharlal Nehru Stadium in Shillong on Saturday. The win helped BFC move up to fourth while Lajong slipped to fifth in the I-League table.
Bengaluru took the lead in the 26th minute when Chhetri slotted the ball home after being put through by Alwyn George. They had a chance to double the lead when Juanan Gonzalez stole the ball from Lajong midfielder Yuta Kinowaki, but the former's shot from distance was saved by Vishal Kaith.
League's top-scorer Aser Dipanda came close to equalizing for the hosts in the first half, but his header from a free-kick was just wide.
Bengaluru doubled their lead in the 49th minute as Khabra headed in Nishu's cross from the deep to score his first for the club.
BFC next host DSK Shivajians while Lajong travel to Mumbai.