India's Bharatiya Janata Party has admitted its "India Shining" approach was harmful in its recent unsuccessful election campaign.
"We never expected such a verdict," admitted Mr Advani
Speaking for the first time since the BJP was ousted, former deputy premier LK Advani said the catchphrase was "not wrong... but not appropriate".
Congress became the biggest party in parliament after a campaign pledging to improve the plight of India's poor.
However, Mr Advani warned the result had not given Congress a clear mandate.
Mr Advani said the two catchphrases "Feel Good" and "India Shining" had hurt the BJP.
He admitted his party had failed to communicate to the poor that five years was too short a time to achieve equitable development.
"In retrospect, it seems that the fruits of development did not equitably reach all sections of our society", he said.
But Mr Advani also attacked Congress and leftist parties for what he called a viciously negative campaign that claimed India had been ruined by the BJP.
"The tone and content of their campaign was such that poverty and unemployment did not exist during the long Congress rule but were actually the creation of the [BJP-led] government," he said.
"India Shining" did not sway the poor hundreds of millions
Mr Advani said the BJP had "never expected such [an election] verdict and it won't be wrong to say that nobody else, including our rivals, expected it either".
He said he hoped Congress understood that the election result was a "divided" one and would act accordingly.
Mr Advani said the result was a combination of state verdicts that had a national effect.
He said the BJP accepted its defeat and pledged to provide "constructive opposition".
However, Mr Advani said the party would bounce back.
"The BJP's future is bright. The setback we have received is temporary. I am confident that we will be back. And we will play our part in fulfilling the dream that we have of a great India.
"While self-criticism is very much needed, there should be no self-flagellation," he said.
Mr Advani said the BJP's defeat had also triggered a debate about its "Hindutva" ideology, which the BJP defines as Indianness but its opponents say means Hindu nationalism.
He said the party remained firm and unapologetic about its espousal of Hindutva.
"We shall continue to wage an ideological battle against those who portray Hindutva as communal for their narrow-minded political ends," he said.
Modi under fire
Further fallout hit the BJP alliance on Friday with Chandrababu Naidu of the key ally, the Telugu Desam Party in southern Andhra Pradesh state, blaming the BJP for the poll rout.
Mr Naidu, the recently defeated state chief minister, said the BJP had blundered in not removing its Gujarat chief minister, Narendra Modi, after the communal violence there in 2002.
Mr Modi has also come under fire from within Gujarat, with one legislator openly seeking his removal.
But the BJP denied there was any resentment and said there was no question Mr Modi would be sacked.