Delhi's defeated Chief Minister Sheila Dikshit had ridiculed the AAP's debut while the BJP had derided it as the Congress' "B-team". Rated by its adversaries as an upstart and an also-ran, Aam Aadmi Party, which literally translates to the Party of Common Man, Sunday made history in Delhi assembly polls, marking an unprecedented debut feat in the electoral history of India.

The party emerged a close second with over 25 seats, relegating the ruling Congress to the third spot and preventing a Bharatiya Janata Party sweep of the capital. The biggest upset of the election was the victory of AAP's chief campaigner Arvind Kejriwal over three-time chief minister Sheila Dikshit.

AAP's splash in Delhi is likely to have wider political ramifications and give it strength to expand its base in other parts of the country. The party scored victories not only in seats with sizeable presence of poor and working classes but also those considered posh areas such as Greater Kailash.

Formed a year back, the AAP promised a clean break from politics of the past and tackle people's disenchantment with a system perceived to be loaded in favour of the rich and the powerful. With limited resources at its command, the party chose to fight only in Delhi among the five states that went to the polls November-December.

Unlike the Congress and the BJP which have several leaders and campaigners with popular appeal, AAP had only Kejriwal, 45, as its most visible and prominent face.

The IIT engineer-turned-taxman-turned-political activist had built a reputation as an anti-corruption crusader through his work in NGOs. He plunged headlong in the electoral challenge by pitching himself against Sheila Dikshit in her New Delhi constituency. The move, audacious and unconventional for a newcomer to politics, put AAP in the centrestage of neighbourhood discussions about prospects of various parties in Delhi.

AAP was born on an anti-corruption plank following an agitation on the Lokpal bill and zealously guarded its image throughout the campaign as a party which gave topmost priority to tackling graft.

The party sought to live up to its promise of "clean politics" by putting out list of all its donors irrespective of the amount of money they gave to the party. After its candidate from Rajouri Garden was found to have hidden information from the party about a pending case relating to dowry, AAP withdrew its support to him.

AAP was the first to declare its candidates and made efforts to ensure they had clean credentials. In its campaign, AAP focused on issues that rankle the middle class and the poor - corruption, price rise, access to water, cost of electricity, inadequate public heatlh facilites and poor state of government schools. It also focused on the issue of women's security.

While the middle class and the intelligentsia was apparently impressed by AAP's unflinching focus on tackling corruption, AAP assiduously worked among the poorer sections - including rickshaw pullers and vendors - and promised to tackle their woes.

As a new entrant which was up and against established and seasoned political players, AAP chose an unconventional way to campaign and cause ripples. It chose the back of the ubiquitous auto-rickshaws to target its key adversary - the Congress government of Sheila Dikshit. It used the similar tactic hit out at the BJP.

AAP's promise to tackle graft and its promise to break with the past attitude of "chalta hai" (let it be) in governance attracted volunteers from different parts of country. Some took breaks from their jobs to give strength "to the new experiment" in Indian politics. The party also attracted support of many non-resident Indians who made contributions to the party's poll coffers.

The party's campaign was steered by its political affairs committee which started held daily meetings months before the elections. The committee has activist-lawyer Prashant Bhushan and social scientist Yogendra Yadav as members.

The party had strong online presence to attract young voters. Its choice of the humble broom as its election symbol not only helped it identify with the underprivileged sections but was also symbolic of its desire to "brush clean" politics and its adversaries.

The Congress and the BJP, which were dismissive or disdainful of the AAP, grew increasingly queasy as the campaign progressed and began complaining about the new party's tactics. A sting on AAP candidates threatened to puncture its campaign but the party tackled the issue upfront.

Delhi elections were crucial for the AAP in its aim to be a party with a long haul. It was also important for the party's desire to expand its base outside Delhi.

Political analyst S. Nihal Singh said AAP had started on a fantastic note. "It is a vindication of their sense of idealism. It is a stunning result for AAP and for what Kejriwal believed in," Nihal Singh told IANS.

He said Kejriwal had gone a step forward over his "guru" Anna Hazare.

Nihal Singh, however, said it would not be easy for AAP to replicate its performance in other parts of the the country as factors such as caste had much larger influence in some states compared to Delhi.