The BJP and its ally Apna Dal (S) consolidated their position in politically crucial Uttar Pradesh by bagging 15 seats and leading in 49 others, while the rival SP-BSP alliance has won five seats and is leading in just 10 out of 80 seats.
Prime Minister Narendra Modi won from Varanasi seat defeating his nearest rival SP's Shalini Yadav by a huge margin of 4,79,505 votes, bettering his previous margin.
While Modi got 6,74,664 votes, Shalini got 1,95,159 votes and Congress candidate Ajay Rai bagged 1,52,548 votes.
In the 2014 general election, Modi had won by the margin of 3,71,784 votes from his nearest rival AAP leader Arvind Kejriwal. According to the trends available till 9 pm, the BJP has won 13 seats and its ally Apna Dal (S) two seats.
The BSP was leading in six seats, SP in four and Congress in one seat, they said.
In Aligarh, BJP's Satish Kumar Gautam defeated BSP candidate Ajeet Baliyan by 2,29,261 votes. R K Singh Patel of BJP defeated Shyama Charan Gupta (SP) by 58,938 votes in Banda, while in Unnao, Swami Sakshi Ji Maharaj (BJP) defeated Arun Shanker Shukla (SP) by 4,00,956 votes.
The BJP also bagged Bahraich and Gorakhpur seats, while its ally won from Robertsganj.
Mayawati-led Bahujan Samaj Party (BSP) opened its account by winning from Nagina Lok Sabha seat. The party had drawn a blank in the 2014 Lok Sabha polls from the state.
In Bahraich, Akshaywar Lal of BJP won by defeating Shabbir Balmiki of Samajwadi Party by a margin of 1,28,752 votes.
Gorakhpur seat was wrested by Bhojpuri star and BJP candidate Ravi Kishan by defeating SP's Rambhual Nishad by a margin of 3,01,664 votes. In the by-election, the seat was won by the SP-BSP combine.
Robertsganj seat went to Pakauri Lal Kol of BJP's alliance partner Apna Dal (Soneylal) who defeated his closest rival Bhai Lal of Samajwadi Party by 54,336 votes.
The BSP won from Nagina where its candidate Girish Chandra defeated Yashwant Singh of BJP by a margin of
"Kaun kehta hai aasmaan mein suraakh nahin ho sakta," she tweeted after leading by over 45,000 votes in the seat considered a Congress bastion. Her tweet came immediately after Gandhi conceded defeat and congratulated the minister.
The 43-year-old BJP leader took the political hotbed of Amethi by storm after trends indicated that she was heading for a win in the Gandhi-stronghold.
The Congress chief had also contested the Lok Sabha election from Wayanad in Kerala, a decision political pundits believed was widely influenced by the tough fight Irani posed to him in his home turf.
The Gandhi scion had defeated Irani in 2014 by a margin of 1.07 lakh votes.
In neighbouring Rae Bareli constituency, Rahul's mother and UPA chairperson Sonia Gandhi led over her nearest rival by over 1.67 lakh votes to give the grand old party a saving grace.
Chief Minister Yogi Adityanath attributed the impressive show by his party to the "alert voters" who he said rejected the 'mahagathbandhan' (grand alliance) of opposition parties.
"It is high time for the opposition to introspect and shun politics of negativity," he told PTI, giving full credit to Modi and BJP president Amit Shah for the "historic victory".
As the trends indicated a clear picture, BSP supremo Mayawati said she had not contemplated that the BSP-SP-RLD alliance will fare so badly.
Expressing doubts over the outcome, she said most of the parties want the elections to be conducted through ballot papers.
Mayawati added the alliance partners will sit together to decide the future course of action following such "unprecedented" results.