Reports suggest that Suraj secured 9799 votes as against 8856 bagged by Jayadev.
Suraj is the son of Congress MLA E Kunjeshore, whose sudden and untimely death necessitated the by elections.
The polling was held on Saturday, Dec 19 and counting was done on Wednesday, Dec 23.
With this victory, Congress has a strength of 31 seats in a 60-member assembly.
Congress along with the CPI, which has 3 seats, form the ruling Congress-led Secular Progressive Front (SPF) ministry in Manipur.