The biggest celebration was on at the AAP headquarters at East Patel Nagar in west Delhi where thousands of Aam Aadmi Party activists as well as supporters cheered every time the party won a seat.
Many waved AAP flags and others held photographs of party leader and former chief minister Arvind Kejriwal.
AAP leader Arvind Kejriwal was leading in the prestigious New Delhi constituency while BJP's Chief Ministerial nominee Kiran Bedi was trailing in Krishna Nagar seat, considered a traditional stronghold of the party. Congress' Ajay Maken was trailing in Sadar Bazar seat.
As trends showed AAP's possible victory, Bedi said she will take responsibility if BJP was defeated in the polls.
“We (me and Kejriwal) both are competing. We both are playing a match. When we play, only person has to win. If the party wins, it will be a collective victory and if the party loses, I will take the responsibility,” Bedi told reporters at her residence.
Bedi was trailing after first round of counting. AAP candidate and former Minister Rakhi Birla was leading in Mangolpuri constituency in North West Delhi against her Congress rival Raj Kumar Chouhan.
Another former AAP Minister Somnath Bharti was ahead in Malviya Nagar constituency in South Delhi over his Congress opponent Yoganand Shastri.
AAP leader and former Minister Manish Sisodia was leading in Patparganj seat in East Delhi against ex-AAP MLA and BJP candidate Vinod Kumar Binny. BJP's Jagdish Mukhi was ahead in Janakpuri.
Former AAP Minister Sourav Bhardwaj was leading from Greater Kailash where Congress' had fielded President Pranab Mukherjee's daughter Sharmistha Mukherjee.
