"At some places, Congress has won while in other places it has lost. The BJP leaders are unnecessarily projecting it has a big victory," Karnataka Congress president G Parameshwara said in a press release.
Elections are due in Karnataka in a couple of months.
State BJP chief BS Yeddyurappa said the people of North-East in general and Tripura in particular have rejected the "corrupt and divisive" politics, practised by the Congress and the CPI (M).
"It is now clear that the people of Karnataka will also reject the Congress for its corruption, collapse of law and order and divisive politics being unleashed by Siddaramaiah," he said in a release.
"The writing on the wall is crystal clear the countdown of the Congress has begun," he added.
Union Minister Ananthkumar said the Congress has lost its base substantially across India and is limited to Karnataka, Punjab and Puducherry.
"It is the writing on the wall (for the congress)," he told PTI.
According to Rajya Sabha member Rajeev Chandrasekhar, the Congress is losing its relevance in national politics and the same may broadly apply to Karnataka as well.
"People in Karnataka are fed up with rampant corruption...the Congress and CPI (M) are in a race to lose their relevance and at present CPI (M) is leading," he said.
The BJP wrested Tripura from the CPI-M, securing a majority on its own, while in Nagaland it has received an invitation from NPF leader and Chief Minister TR Zeliang to join the new government.
In Meghalaya, BJP could manage just two seats while its North-East Democratic alliance partner National People's Party won 19.
The Congress, which was in power in Meghalaya since May 2009, failed to win a majority but emerged as the single largest party with 21 seats.