Payne (9th, 33rd) scored a first-half brace while I-league top-scorer Dipanda Dicka (64th) netted his ninth goal of the season but it proved to be in vain.
The win took Trevor Morgan's team to 27 points from 12 games, one ahead of second-placed Aizawl FC who won 2-0 earlier in the day. Lajong have 16 points from 11 outings.
The visitors took the lead within nine minutes, Payne making the most of some slack defending and goalkeeping by Lajong to score his first goal for the visitors.
Three minutes later, coach Thangboi Singto's wards almost drew level but Dicka put Isaac Vanlalsawma's delectable cross inches wide.
The whole stadium started celebrating when Bipin Singh dragged a thunderous volley just wide after creating the move by setting up Vanlalsawma, whose initial shot was half cleared by East Bengal defenders.
Bipin was outstanding in the half, carving out a delicious chance for Samuel Shadap.
But just when it looked like the hosts were spurred after the early setback, East Bengal doubled their tally against the run of play.
Payne was at it again, chesting down a free kick calmly from the halfway line and slotting home a volley with keeper Vishal Kaith left stranded as East Bengal went into the break 2-0 up.
In the second half, the home team started with more flair and got their reward four minutes into the hour mark.
Dicka got on the end of a beautiful Shadap lob inside the box after the latter was set up expertly by Yuta Kinowaki with a cross field pass.
In the 71st minute, Lajong came close to levelling things but T.P. Rehenesh saved well from Shadap's shot from outside the box.