After the BJP's maiden government in south India was routed in May 5 elections, the party on Wednesday lost its claim to the main opposition in the Karnataka assembly.
Despite securing the same number - 40 - of seats in the House, the saffron party lost the status to HD Deve Gowda's JD(S) on account of a tad lower vote share.
According to the Election Commission, the JD(S) had 20.09% vote share (62,69,907 votes) while BJP had a 19.97% vote share (62,32,595 votes) for their 40, each, MLAs.
Under Gowda's son and former chief minister HD Kumaraswamy, the JD(S) will now be, for the first time, the principal opposition party.
On Wednesday, Kumaraswamy said, "We would be a responsible opposition party and have our task cut out as the watchdog in the present situation. I have asked all my MLAs to watch out each department for any misdoings in the coming days."
The Congress bagged 121 seats in the 225-member assembly and is set to form the government under Siddaramaiah.
Meanwhile, the BJP selected former CM Jagadish Shettar as their leader, while former CM DV Sadananda Gowda would be its leader in the Legislative Council.
Sadananda Gowda said that his party would work positively for the development of the state.
CM Siddaramaiah, meanwhile, met national leaders in Delhi on Wednesday to finalise his cabinet of ministers. The names are likely to be finalised by Thursday.
KPCC chief G Parameshwara is also camping in Delhi since Tuesday.
More than 80 MLAs are also camping in Delhi to lobby for berths in the Siddaramaiah cabinet. A senior leader said the Karnataka Bhavan was packed with the MLAs.