Congress wrestled the Valpoi seat in the by-poll on Thursday with its candidate Vishwajit Rane winning the election by margin of over 8,000 votes.
BJP's Santosh Haldankar was defeated in the poll which saw Congress winning over the seat comfortably.
Congress polled 11,642 votes and BJP could get only 3,237 votes.
The counting for the by-poll began at 0800 hours on Thursday morning at Campal near Panaji. The polling had taken place at October 18 for this crucial seat.
For the first round, Rane led with 3,000 votes polling almost 90 per cent in the Valpoi city, which is considered as Congress stronghold.
Rane increased his lead to 5,878 votes after second round of counting and his victory was confirmed.
Total 14,881 voters had cast their votes notwithstanding the rains that hit this rural taluka.
Congress had contested the poll on development issue while BJP had asked for votes claiming that Rane was encouraging mining in this taluka ruining the greenery.
The by-poll in this constituency was necessitated after Rane, state's health minister and independent candidate, resigned as member of Legislative Assembly and joined Congress on June 24, 2010.
After losing the elections, Haldankar said that increasing use of money by Rane engineered his defeat."There was massive use of money power. We could not counter this power," he said.