Buoyed by the win in the Kairana parliamentary by-election, he said public opinion and electoral results such as the by-election victory will act as a "glue" for cementing a coalition for the Lok Sabha polls next year.
Rashtriya Lok Dal or RLD candidate Tabassum Hasan, who was supported by the Samajwadi Party, the Bahujan Samaj Party and the Congress, triumphed last week over her BJP rival in Kairana to become the first Muslim face from Uttar Pradesh in the 16th Lok Sabha.
Her victory also gave RLD, its first representative in the current Lok Sabha after the party drew a blank in the 2014 general election.
In an interview to news agency PTI, Mr Chaudhary said the BJP wants to make the 2019 polls a battle of personalities, but the opposition wants to project issues rather than a personality to take on Prime Minister Narendra Modi.
"They (the BJP) have built a personality cult around Narendra Modi and now they expect the opposition to also thrust upon the nation a similar figure so that the two can sort of take each other on," the 39-year-old leader said.
Mr Chaudhary, who is the son of RLD chief Ajit Singh and the grandson of former prime minister Chaudhary Charan Singh, said there was more talent in the opposition ranks and more freedom to express than in the BJP.
"So I think going into 2019, I am not sure there will be an understanding of who's on top and who's at the bottom (of the opposition alliance), but we will be working together. That is important for the country," he asserted.
Asked if Congress being a pan-India party could be the pivot of the opposition alliance to take on the BJP, he said, "Congress today is the largest opposition party and they have an organisation in most states of the country that is still strong.
"...I see a good story emerging. Congress can definitely play that role. They can cooperate and collaborate more effectively than the BJP."
He said that due to the manner in which the BJP has dealt with its own allies, their alliance partners were either breaking away or speaking very openly against it. "So, the Congress has an opportunity here to try and make new relationships with these partners as well," he said.
Asked if the Congress was more capable of building alliances and working in unison with parties in an alliance, Mr Chaudhary said, "That's my perception, (and) that is the perception of a lot of people in the political system."
Mr Chaudhary, whose party RLD has been in an alliance with the BJP in the past, also alleged that there was arrogance that had crept into the BJP and it was no longer 'the party with a difference'.
The BJP leads the NDA coalition at the Centre which includes several parties such as the Shiv Sena and the Lok Jan Shakti party. The N Chandrababu Naidu-led Telugu Desam Party recently quit the NDA, while Shiv Sena has been critical of the BJP over several issues.
Mr Chaudhary also asserted that if the alliance between his party, the Samajwadi Party, the BSP and the Congress in UP takes shape, it would help the Congress in states where it is involved in a direct contest with the BJP.
"I think ultimately it (the alliance in UP) will help Congress in the states where it is taking on the BJP, there numbers will go up...If Congress takes us along and tells us that lets work together in other states as well, some of these opposition leaders will be very willing to do that," the former MP said.
Acknowledging that seat sharing would not be easy for the grand alliance in UP, he said the "social coalition" formed was more important than just simple political arithmetic or simple political coalition.
"So to sustain that social coalition, if political parties have to forego their own interest and work together, I think we should do it," Mr Chaudhary said.
Talking about the Kairana bypoll win, he said it was basically a message to political parties that the alliance was also the people's will.
"It was a negative vote against BJP. It was also a positive vote for the opposition working together. Going forward it is this public opinion and these good results that will perhaps act as the glue for cementing the alliance," Mr Chaudhary said.
The united opposition victory in Kairana follows the BJP defeats in the Lok Sabha bye-elections in Gorakhpur and Phulpur in March, and come just a year before the general election.
Asserting that alliances are here to stay, Mr Chaudhary said the reason he feels the alliance in UP would continue was because it has tasted success.
"When you win an election, there is pressure from your workers, there is pressure from the voters to continue. That is why I think, there is enough mature leadership in all of these parties, they have enough experience, they will be able to work out an arrangement on the seats," he said.