Bangalore South BJP MLA M Krishnappa pulled out from Bangalore Rural, while K S Doreswamy did so in Mandya on the last day of withdrawals, leaving the field to a direct fight between the Congress and JDS.
In a quid pro quo, JDS did not field candidates for August 22 Legislative Council poll from Dharwad, Chitradurga and Mysore Local Authorities constituencies, apparently in favour of the BJP.
While the former Prime Minister Deve Gowda insisted earlier this week that there is no truck with the BJP, his son and state unit President H D Kumaraswamy maintained that his party's primary objective is to defeat the Congress.
After getting elected to legislative Assembly in May, Kumarswamy had resigned his Bangalore Rural seat, while his party colleague N Cheluvarayaswamy from Mandya Lok Sabha seat, necessitating the byelections.
For its part, BJP leaders say in private that the party does not fancy a chance to win in both Mandya and Bangalore Rural and does not want to cut a "sorry figure" if it were to get a poor vote share and terms the move to join hands with the JDS as a "political strategy".
JDS has fielded Kumarswamy's wife Anita from Bangalore Rural and C S Puttaraju from Mandya, pitting them against D K Suresh, brother of former Minister D K Shivakumar, and cine actor Ramya, respectively.