Norde (35th) scored from a free kick while Mallick (43rd) doubled the margin with a dinked effort from the edge of the box as Bagan trimmed the gap to one point on Aizawl who lost earlier in the day to defending champions Bengaluru FC by a solitary goal.
Rowlin Borges pulled one back for the visitors in the second half injury time.
Bengaluru FC's Serbian recruit Marjan Jugovic ensured both Kolkata outfits had everything to play for ahead of the derby by scoring the winner for Bengaluru against surprise leaders Aizawl who remained on 30 points from 15 games.
Bagan, on 29 points after the convincing win, have a game in hand to both Aizawl and East Bengal who stayed on 27 points from 15 outings.
East Bengal's Trinidad & Tobago import Willis Plaza was given marching orders in the 66th minute.
In Siliguri, as expected, it was end to end stuff from the first whistle. Bagan got two early chances with Darryl Duffy and Balwant Singh taking a swipe at goal from 35 yards and the edge of the box respectively.
At the other end, Plaza headed down a Mehtab Hossain floater for a lurking Wedson Anselme whose shot was deflected off a Bagan defender for a corner from which nothing transpired.
Bagan centre-back Eduardo Fereirra then almost made a hash of a regulation backpass with Plaza bearing down on him forcing home team keeper Debjit Mazumdar to avert the danger.
Balwant came close at the other end with a volley on the turn which sailed over the bar while Norde dribbled past few defenders to sky his attempt.
Norde made amends minutes later, curling in a delectable free kick that beat East Bengal goalkeeper T.P. Rehenesh all ends up to nestle into the top right corner.
Azharuddin doubled the Sanjoy Sen coached side's tally sending the sparse Bagan supporters in a tizzy two minutes before halftime. Picking up the ball from Duffy, the lanky Under-22 player waltzed past East Bengal players and chipped the ball over an onrushing Rehenesh from outside the box. The ball took a deflection off the post to sneak in.
In between both the goals, East Bengal coach Trevor Morgan replaced U-22 player Abhinas Ruidas for Austraian striker Chris Payne in search of an equaliser.
The red and gold shirts started with more intent post the break, with Payne forcing Mazumdar into a good save early on.
But it was not the away side's night as Plaza was sent off for a reckless challenge on Bagan defender Anas Edathodika.
As the match neared its final whistle, East Bengal players seemed to losing their cool, engaging in hasty duels and verbal exchanges with their counterparts.
Morgan tried to inject pace by introducing the nippy Jackichand Singh in place of Romeo Fernandes as East Bengal threw everything but the kitchen sink in the dying minutes of the match.
Borges got a goal back too in second half added time but that proved to be too little too late as East Bengal were left red faced with their rivals stealing a march on their bitter rivals.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
About VDC
Doraiah Chowdary Vundavally is a Software engineer at VTech . He is the news editor of SocialNews.XYZ and Freelance writer-contributes Telugu and English Columns on Films, Politics, and Gossips. He is the primary contributor for South Cinema Section of SocialNews.XYZ. His mission is to help to develop SocialNews.XYZ into a News website that has no bias or judgement towards any.