Two second half goals were enough for the Pune side as they notched up an impressive victory in the first home fixture of their campaign.
The goals were scored by youngster T. Haokip and Australian James Meyer in quick succession in the second half, after Anyichie Echezona had got sent-off.
Pune FC welcomed back Raul Fabiani in their line-up, after the forward missed the last game due to being suspended, with Douhou Pierre moving to a more conventional attacking midfield position.
Mohun Bagan meanwhile persisted with Eric Muranda with Katsumi Yusa just behind him.
The Red Lizards started dominating proceedings right from the off, infront of their vociferous supporters, with the quartet of Nikhil Kadam, Douhou Pierre, Fabiani and James Meyer linking up delightfully.
Kadam regularly burst through the right wing using his electric pace, and almost slid in a beautiful ball for Fabiani in the opening minutes of the game, but the keeper intervened.
Calum Angus then tried his luck from a long range freekick which did not trouble the keeper.
Katsumi Yusa at the other end reminded the home side of his threat, undertaking several mazy runs, but they generally ended in frustration, as Muranda failed to read his partner’s passes.
Fabiani then wasted the best chance of the half, when he failed to direct the ball on target after Gurjinder Kumar found him with a promising cross.
Mohun Bagan then had two decent chances, but Katsumi Yusa skied his effort well off-target and Anyichie Echezona hit his header straight at Amrinder Singh.
The tempo of the game visibly slowed down thereafter, and both sides seemed content to see out the half with the deadlock yet to broken.
The second half promised to be better, as almost immediately after kickoff, Muranda had a golden opportunity to put his side ahead, as he beat Amrinder Singh to a long punt forward and looked set to tap the ball into an empty net, but Calum Angus came out with a game saving tackle to deny the forward.
However the match was turned on its head, when Anyichie lost his cool, and lashed out at Fabiani after the latter had initially fouled the Bagan defender with a raised foot. Referee decided to book Echezona which was his second booking and was thus asked to leave the field.
The Red Lizards though, were also going to receive a set-back soon after, as Raul Fabiani limped out, with T. Haokip replacing him.
But it proved to be a master-stroke, as from a Calum Angus freekick a little while later, the forward headed his side ahead in the 72nd minute.
As expected, the Red Lizards were making the most of their man’s advantage, dominating possession, and soon went 2-0 in the lead, when Meyer slotted home a fine cross by Othallo Tabia in the 79th minute, to almost surely seal the deal for his club.
The Australian could have rubbed further salt into the Mariners’ wounds, but his shot after some brilliant linkup play with Haokip was just wide of the post.
Mike Snoei’s side then coasted through the rest of the game, registering a comfortable 2-0 win in their first home game of the season.