The victory margin was 11,468 votes.
Aam Aadmi Party's Durgesh Pathak on Sunday defeated BJP candidate Rajesh Bhatia by a margin of over 11,000 votes in Rajinder Nagar assembly bypoll here, officials said.
"All 16 rounds of counting have been completed. AAP candidate Durgesh Pathak has defeated his immediate rival Rajesh Bhatia (of BJP) by a margin of over 11,000 votes," Delhi Chief Electoral Officer Ranbir Singh said.
According to official data, AAP's Mr Pathak polled 40,319 votes, while his nearest rival Mr Bhatia managed to get 28,851 votes. The victory margin was 11,468 votes.
Congress' contender Prem Lata could get only 2,014 votes in the bypoll.
The poll panel is yet to come out with the final voting figures.
The bypoll to the crucial assembly seat had taken place on June 23 with a low turnout at 43.75 per cent. Fourteen candidates threw their hats in the fray, which has largely been seen as a battle between a confident AAP and a spirited BJP.
Counting of votes had begun at 8 am amid tight security arrangements.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)