The BJP suffered an embarrassing reverse in Ballari, a seat it had been winning since 2004 with a vice-like grip of the mine-rich district by the controversial Reddy brothers, but it managed to hold on to the Shivamogga Lok Sabha seat.
Buoyed by the victory in the bypolls, Karnataka Chief Minister H D Kumaraswamy and Congress state president Dinesh Gundu Rao Tuesday asserted that they would contest the 2019 Lok Sabha elections together against the BJP.
The JDS-Congress victory is seen as emphatic endorsement of the coalition by voters. The electoral performance comes as a booster to the combine as the bypolls were seen as a barometer of the public mood ahead of the Lok Sabha polls.
Both the coalition partners had put up joint candidates in the bypolls, which was also considered a test of their ties.
In Ballari, Congress's VS Ugrappa won the seat by more than 2.43 lakh votes over BJP's J Shantha, the sister of B Sriramulu, a key aide of the Reddys and former MP from there.
Sriramulu is considered a close confidant of Janardhana Reddy, but the BJP had distanced itself from the mining baron in the May assembly polls with party president Amit Shah making the party position clear.
The BJP's loss was attributed to factors including non-involvement of the Reddy brothers -- Janardhana Reddy is barred from entering Ballari district in an illegal mining case -- and the party depending solely on Sriramulu with its leaders not taking a wholehearted plunge into the campaign.
The Congress had invested much prestige and men and material into the fight. The result also reflects the assembly poll outcome trend with the Congress then having won six of the eight seats.
Ballari had been a Congress pocketborough till 2004 and had elected Congress leader Sonia Gandhi in the 1999 Lok Sabha polls against BJP's Sushma Swaraj. Since 2004, the influence of the powerful and mighty Reddy brothers was evident in what was infamously called 'Republic" of Bellary.
In Shivamogga, the traditional stronghold of Opposition leader and former chief minister BS Yeddyurappa, his son BY Raghavendra defeated his JDS rival Madhu Bangarappa by 52,148 votes in a closely fought contest.
Madhu is the son of former Congress chief minister, the late S Bangarappa.
Kumaraswamy's wife Anitha bagged the Ramanagara assembly seat by a big margin of 1,09,137 votes against her nearest rival BJP's L Chandrashekar, who had pulled out of the contest, but still officially remains the party candidate.
Chandrashekhar, who had joined the BJP ahead of the polls returned to Congress weeks later, leaving the saffron party red-faced and the field open for a walkover for Anitha Kumaraswamy.
Ramanagara seat fell vacant after Kumaraswamy preferred to retain Chennapatna, the other constituency from where he had won.
In Jamkhandi assembly segment, Congress candidate Anand Nyamgouda defeated BJP's Srikant Kulkarni by a margin of 39,480 votes, riding a sympathy wave following his father and sitting MLA Siddu Nyamagouda's death in a road accident.
JD(S) candidate L R Shivarame Gowda scored a huge victory in Mandya, defeating BJP's Siddaramaiah, a political green horn and a former civil servant by 3,24,943 votes.
Mandya is a stronghold of the Vokkaliga community to which JD(S) supremo and former prime minister HD Deve Gowda belongs.
Significantly, with the election of Anitha, the Assembly will see the husband-wife duo as members in the same House.
With Tuesday's victory, the Congress-JD(S) alliance's tally will go up to 120 seats in the 224-member assembly, where the BJP has 104 MLAs.
The BJP had emerged as the single largest party in the assembly polls but failed to muster numbers to form a government, paving the way for the JDS-Congress combine.
Elated over the performance of the ruling alliance candidates, jubilant Congress workers distributed sweets and broke coconuts at various places.
Jubilant over the results, chief minister Kumaraswamy said, "We will contest the 2019 Lok Sabha elections together. As we did this time, we will sit together to chalk out strategies to fight the Lok Sabha election in a coordinated manner."
Gundu Rao said, "It (the electorate) has rejected the BJP, its divisive politics and dictatorial tendencies. We will contest the 2019 election together," he said.
Apparently unhappy with the outcome, Yeddyurappa alleged, "The truth of the matter is that money and liquor had a bigger role in this election. Congress and JD(S) won the election by misusing money and power."
Karnataka is the only south Indian state where the BJP has been in power--from 2008 to 2013.
The by-elections for three Lok Sabha seats were necessitated after Yeddyurappa and Sriramulu of the BJP and CS Puttaraju of the JD(S) vacated Shivamogga, Ballari and Mandya following their election to the assembly in May.
Bypolls to Jamkhandi seat was necessitated following the death of sitting Congress MLA Siddu Nyamagouda, while Ramanagara fell vacant after Kumaraswamy gave it up.
BJP had held the Shivamogga and Ballari Lok Sabha seats and JDS Mandya. Congress had won Jamkhandi and JDS Ramanagara in the May 12 assembly polls.