Sajandeep Singh scored the first goal for the winners in the 15th minute, followed by Prem Kumar (25th) and Afftab Vir Singh (46th).
West Bengal made a stupendous come back as they reduced the margin when Jagannath Sana (66th), Dibendu Biswas (76th) scored quickly in the second half.
For Punjab, the fourth goal came again from the boots of Prem Kumar in the 79th minute.
Though Bengal fought relentlessly thereafter, they could score only one goal in the last minute of the game through Nabin Hela.
Captain Mmeino scored the lone goal for Manipur in the 63rd minute of play, while Amoes T found the third goal for the winners in the 83rd minute.