Following initial results, Khan's center-right Pakistan Tehreek-e-Insaf (PTI) was brought to power, gained an unexpectedly strong mandate, but failed to win a majority in the National Assembly.
In the last official census, Khan's party had won 119 seats out of a possible 272 seats, with 219 declared.
The apparent victory of the 65-year-old populist who campaigned as a "change"
The candidate who relies on the construction of a "new Pakistan" became widely regarded as "historic" for the break of the two-party duopoly  that dominated national politics for decades,  on its enormous popularity as a sports celebrity and The PTI's success as a regional party, its anti-graft mantra struck at disenchanted young and middle-class Pakistanis.
However, the delayed election results have compounded the cries of fouling after every political party, with the exception of Khan's alleged electoral fraud. Some claim that their observers did not receive final figures or were asked to leave the polling stations before the census ended.
"If they take to the streets, there could be significant riots," said Michael Kugelman, South Asia expert in the US Wilson Center.
"Given that apparently every Pakistani political party, which is not a PTI fraud allegation, there could be quite a few people on the street. "
The election – only the second democratic transition in the 71-year history of Pakistan – was also overshadowed by hundreds of political arrests, a massive one Repression of the media and growing tensions over allegations that the powerful military secretly supported Khan.
Former Prime Minister Nawaz Sharif was dismissed last year on corruption charges, leading to his arrest earlier this month
Sharif's brother, Shahbaz, leader of the established Pakistan Muslim League (PML-N), said on Twitter have given "massive rigging" in favor of Khan.
The leader of the Pakistani People's Party (PPP), Bilawal Bhutto Zardari, son of the late leader Benazir Bhutto, also went to Twitter to say that he was dismissing the results on grounds of concern over electoral fraud and said that this was "unpardonable (and) outrageous. "
Analysts said tensions could increase as international organizations monitoring the election voiced uncertainty about the fairness of the election.
The European Commission team should give its verdict on Friday. Parties that have rejected the vote are scheduled to meet on Friday to agree on a common strategy.
"Allegations of procedural irregularities in the post-election phase of several parties need to be investigated," columnist Mosharraf Zaidi said, adding to the electoral commission to explain the delay in announcing the results, especially in Karachi, Pakistan's largest city where the results were against expectations.
On Friday morning, the possibility of change seemed to be returning. The PML-N said it would not boycott the National Assembly, the daily Dawn reported, which would have been a significant setback for Khan.
The prospect of prolonged agitation or protests is limited, Zaidi said other major parties have done relatively well in the polls.
Allegations of election manipulation are widespread in Pakistan. In 2014, thousands of Khan's supporters marched in the capital Islamabad to demand Nawaz Sharif's resignation over alleged electoral fraud during the recent parliamentary elections.
They held a four-month protest that analysts said they had sympathized with the army to obstruct Sharif's rule
"The military is unlikely to support the opposition this time, and national and international observers conclude come that it was a fair election, the dynamics of the opposition will subside, "said Umay Javed, a political analyst.
Javed said that Khan could also avoid a political confrontation by negotiating with the parties. PML-N members can exchange for Nawaz Sharif in return for reducing their 10-year sentence, he said.
The PPP is likely to be subdued because it needs government spending to implement its agenda in its stronghold of Sindh, Javed added.
Opposition to the outcome may also be limited Khan was widely attributed that he had given a statesman's performance that set aside partisan rivalry and demanded unity in the impending economic crisis of Pakistan.
Dawn newspaper that bore much of the brunt of the area code The harsh media crackdown called for a bipartisan reconciliation.
"Imran Khan's acceptance speech yesterday was an encouraging sign," it said in an editorial. "Opposition parties should relay their complaints and protests through official channels."
Many are ready to give a fair chance to a Khan government. Nadir Cheema, an academic at SOAS London, said that although he faces the conservative policies of PTI and its ties to the military establishment, he respects the results.
"Despite the up-front rigging, intimidation and an immature playing field, I support the weakest form of democracy" rather than none at all, "he said.
The leader of the next Pakistani government, an Islamic republic with 207 million people, will face a massive debt crisis and a feverish political atmosphere.
The nuclear-armed state also faces the uncertainty of its relations with the United States – which has cut military aid over Islamabad's alleged support for the Taliban in neighboring Afghanistan – and China, which has financed multi-billion dollar infrastructure projects in the South Asian country.