"No one person is responsible for the defeat. We failed to convince voters," Mulayam, who was ousted by Akhilesh as party chief after the power tussle in the family, told reporters here.
"Everyone is responsible for the loss. A single person cannot be blamed," he said on arriving at Saifai, his native village, for Holi.
"It was people's inclination towards BJP as it has made a lot of promises. Let us see how many promises they fulfill," Mulayam said.
Mulayam's brother Shivpal, who had fallen out with Akhilesh ahead of the polls, had earlier in the day said the party would analyse the reasons behind its poor performance in the polls.
"In politics, you win and lose. SP has its orgins in struggle and we will struggle again and win," he said here.
The BJP emerged as the single largest party in Uttar Pradesh with 312 seats while its allies Apna Dal (Soneylal Patel) and Suheldev Bhartiya Samaj Party bagged nine and four seats respectively.
The Samajwadi Party was relegated to a distant second with 47 seats and its ally, the Congress won seven seats.
Shivpal Yadav vows to fight back
Sidelined SP leader Shivpal Yadav, who won from his seat in Uttar Pradesh where his party suffered a rout, has vowed to fight back in the state.
A day after winning the Jaswant Nagar seat, the warring uncle of Akhilesh Yadav tweeted a 41-second video captioned "Hum phir ladkar jeetenge" (We will fight again to win).
The video shows the leader with Mulayam and also Akhilesh in party meetings.
The 61-year-old SP veteran won the party stronghold Jaswantnagar defeating his nearest BJP rival Manish Yadav Patre by a margin of 52,616 votes.
Though Yadav had been making all out effort to surpass his previous showing, there was a minor drop in the votes polled in his favour.
Last time he had got 1,33,563 votes and his margin stood at 81,084, but this time he polled 1,26,678 votes.
The win was a consolation for Shivpal who was fighting to redeem his lost pride in his native constituency.
"This defeat is neither that of Samajwadi Party nor that of Samajwadis but of arrogance," Shivpal had said yesterday while commenting on the bad showing by his party in the state indicating the bad treatment given to party patriarch Mulayam Singh Yadav and he himself at the hands of the new leadership in the party.
But for the support of Mulayam Singh who had addressed two rallies for him here, Shivpal had walked all alone throughout the campaigning and there were also reports of a concerted move by vested interests in the party to ensure his defeat.
Jaswantnagar, part of Mainpuri Lok Sabha seat, was represented by Mulayam who had won the seat first time in 1967.
Winning it for eight terms he lost on two occasions he left it for Shivpal, who has won it continuously since 1996.