Although the Congress contests this publicly, Congress leaders admit privately that there is a major erosion of support for them among Muslims who may -- unlike in the assembly election in December -- now root for AAP.
A prominent Muslim leader, who did not wish to be named, told IANS that the scenario may be true for many other parts of the country too.
When AAP won 28 of the 70 seats and went on to form a minority government, AAP leader Arvind Kejriwal said publicly that his party did not get the kind of Muslim support it had expected.
Indeed, four of the only eight seats the Congress won came from areas where Muslims live in large numbers.
But the situation is now changing, and radically, AAP and Muslim leaders told IANS.
"During the assembly election, we got only 15-20 percent of all Muslim vote in Delhi," AAP leader Irfanullah Khan said. "In the Lok Sabha election, we expect this to zoom to at least 80 percent."
A well-known Muslim face in the Congress admitted that this may not be an exaggeration, in part because of the aggressive way Kejriwal and the AAP have taken on BJP's prime ministerial candidate Narendra Modi.
"Yes, there is erosion in our (Muslim) support base," said the Congress leader who did not want to be identified by name.
AAP candidates canvassing in the Lok Sabha election are also universally of the opinion that Muslims in Delhi -- which has seven Lok Sabha seats -- are leaning towards the AAP.
Khan, the AAP candidate who lost to the Congress in December from the Muslim assembly constitutency of Okhla, said AAP has been interacting with Muslim intellectuals all over the country for a long time.
AAP leaders, including Kejriwal and Manish Sisodia, have been meeting Muslim academics, those in the corporate field, social activists, religious leaders, retired bureaucrats and former politicians, explaining the AAP ideology and its faith in secular values.
"We are charting a road map for Muslims. But the issues we raise with Muslims are not exclusively for them. These include matters of security, health and education. These are valid for all Indians," said Khan, a member of AAP's decision making core committee.
"So, we are not promising the moon to Muslims. Or making special promises to them. We are for oneness in this country."
He said the traditional Congress argument that Muslims must vote for the Congress "to stop the BJP" was no more finding many takers.
"We tell Muslims that it is we, AAP, who derailed the BJP in Delhi. In 22 assembly constituencies, the BJP finished second. Imagine if we were not there? All these seats would have gone to the BJP," he added.
Muslims make up 12-14 percent of Delhi's 16-18 million people. Traditionally, they have dominantly voted for the Congress in a city where voters had only two main parties to chose from: the Congress and the BJP.
The emergence of AAP has changed the scenario, more so because the party, founded only in November 2012, has gained support cutting across religious, ethnic, linguistic and economic groups.
Salim Engineer, National Secretary for the Jamaat-e-Islam-i-Hind, told IANS over telephone from Jaipur that Muslims were upset with the Congress.
"The Congress could not deliver the promises it made. The community wants a reliable alternative which we see in AAP."
A Muslim resident in south Delhi told IANS: "Muslims have always voted for the lesser evil. That is why we voted for the Congress vis-a-vis the BJP. Now that AAP is there, why not vote for a party which looks good?"
The Congress visibly looks jittery vis-a-vis AAP in Delhi.
Almost every other day, the Congress presents to the media some people who it says are Muslims now disgusted with AAP.
The other day, a dozen men, said to be Muslims, dumped the trademark AAP white caps in the Congress office and donned stole designed on the Congress party's colours.
Says Jamaat's Engineer: "Our people are in touch with AAP. We are impressed by what we saw in Delhi. If they want to do good, why shouldn't we support them?"