Kolkata, Feb 2 (IANS): Former Congress President Sonia Gandhi and Trinamool Congress leader Mamata Banerjee on Thursday congratulated each other for their party's success in by-elections, with the West Bengal Chief Minister calling for one-on-one fight against the BJP.

"The BJP's downfall has started. It will continue and the party will lose power," Banerjee said on a day her party retained the Uluberia Lok Sabha seat and wrested the Noapara Assembly seat from the Congress in West Bengal.

Banerjee also referred to the Congress' impressive showing in Rajasthan where it wrested the Mandalgarh Assembly seat from the Bharatiya Janata Party and won the Ajmer and Alwar Lok Sabha seats by huge margins.

"Soniaji has congratulated me for Bengal election, I have also congratulated her for the Rajasthan results," Banerjee said.

"I still feel parties which have strength in a particular state should fight (the BJP) there with all its strength. There should be one to one (fight). This is what I feel."

Banerjee, however, said there was also a need for electoral adjustments in some areas.

"Again in some areas, there is need for adjustments and re-adjustments. If this is done properly, this (BJP-led National Democratic Alliance) government will not be in the saddle at the Centre after the 2019 elections."

Asked about Trinamool's strong showing in Bengal, she said it was the "victory of the people".

"We are indebted to the people for showering so much love on us. It is the love of the people which inspires me," she added.