JOIN USAs the votes were counted, the Left Front, which had won three of the 10 seats in 2006, led only in Goalpokhar, with the Forward Bloc's Ali Imran Ramoz ahead of his closest rival by about 4,000 votes.
Congress candidate Deepa Dasmunsi was the legislator from this North Dinajpur district seat of north Bengal till her election to the Lok Sabha this year.
The Trinamool Congress bagged four seats - Bongaon, Serampore, Alipore and Rajganj - while the Congress won from its traditional stronghold, Sujapur in Malda district.
The victor in Sujapur was Congress leader A.B. Gani Khan Chowdhury's brother Abu Nasser Khan Chowdhury. He won by a margin of 29,479 votes.
In a startling result, the Gorkha Janamukti Morcha-backed independent Wilson Champamari won from Kalichini in north Bengal's Jalpaiguri district. The Adivasi Vikas Parishad nominee finished second, leaving the more established political parties far behind.
Left Front partner Revolutionary Socialist Party (RSP) finished third and the Congress fourth in the seat, which comprises a large number of tea gardens in the foothills of the Darjeeling Himalayas known as the Dooars.
In Alipore, Trinamool Congress candidate Bobby Hakim trounced his nearest rival Kuastav Chatterjee of the Communist Party of India-Marxist (CPI-M) by over 27,000 votes.
The seat, a Trinamool stronghold, falls under its chief Mamata Banerjee's Kolkata South parliamentary constituency.
Trinamool Congress nominees were ahead in Belgachia (East), Contai South and Egra.
The Trinamool's lead in Belgachia (East) on Kolkata's outskirts was significant as the constituency had elected popular CPI-M leader Subhas Chakraborty seven times. Chakraborty died earlier this year.
To cash in on a perceived sympathy wave, the CPI-M nominated Chakraborty's widow Ramala against Trinamool leader Sujit Bose.
The CPI-M and Trinamool Congress are contesting in five and seven seats respectively. The others have been left for the Left Front allies and the Congress.
With the Left losing its grip over the state under the assault of the Trinamool-led opposition, the by-elections are considered a trailer to the 2011 assembly elections.
However, Saturday's by-elections were mainly held in areas considered opposition citadels. Despite contesting separately, the Congress and the Trinamool won seven of the 10 constituencies in the 2006 elections.