Pakistan Prime Minister Imran Khan has convened a meeting of his allies on Friday to firm up his strategy, a day ahead of seeking a vote of confidence from the National Assembly following a key defeat in this week's closely-contested Senate elections.

Pakistan Democratic Movement (PDM) candidate and former prime minister Yusuf Raza Gilani defeated ruling Pakistan Tehreek-e-Insaf (PTI) candidate Abdul Hafeez Shaikh on Wednesday, in a major blow to Khan, who had personally campaigned for his Cabinet colleague.

The defeat of the finance minister in the elections to the upper house prompted calls for resignation of Khan by the Opposition leaders.

Khan hit back by announcing to seek a vote of confidence from the National Assembly on Saturday. Shaikh was defeated by a margin of 5 votes.

President Arif Alvi has summoned the session on Saturday where Khan’s PTI is determined to prove his majority with the help of allied parties.

Khan is expected to meet lawmakers from Mutahida Qaumi Movement Pakistan (MQM-P), Pakistan Muslim League Quaid-e-Azam (PML-Q) and Grand Democratic Alliance (GDA) to discuss the vote of confidence.

Sources in the PTI said that GDA has some issues as its candidate for Senate seat lost in Sindh Assembly and the Prime Minister would like to address the concerns in the meeting. Similarly, he will try to assure the MQM-P about its concerns regarding the issues faced by Karachi.

Khan needs the support of 171 lawmakers in the National Assembly, currently having 340 members out of total 342, as two seats are vacant.

Minister for Science Fawad Chaudhry said that Khan will easily win the confidence vote as PTI''s woman candidate for Senate, Fouzia Arshad, got 174 votes on Wednesday and won in the house where Shaikh got 164 votes and was defeated.

“The requisite support is available and Khan will easily win,” he said.

Education Minister Shafqat Mahmood said that the vote of confidence will be held in an open setting, which means that it will be hard for any PTI lawmakers to openly defy the Prime Minister.

However, Opposition leaders are calling it a victory that Khan was forced to seek a vote of confidence, saying it was a sign of weakness and will finally lead to his ouster.

“The Prime Minister has lost the moral ground to remain in power and winning the vote of confidence is immaterial,” said Shahid Khaqan Abbasi, former premier and leader of Pakistan Muslim League-Nawaz.

Khan, addressing the nation on Thursday, said that he would sit on opposition benches if the house refused to pose trust in his leadership.

However, it is generally believed that he will come out unscathed from the current political challenge but his problems will not end as the 11-party opposition alliance, PDM, already announced a march on Islamabad on March 26 to topple his government.

But before that an even more interesting round of fighting is expected next week in the Senate, which will elect its new chairman.

The ruling PTI announced to support the incumbent Sadiq Sanjrani, while PDM is expected to field Yusuf Raza Gilani.

In the house of 100, the PDM has a slight majority but the election will be held on the basis of secret ballots and anything can be expected.