Delivering a stunning blow to the ruling Congress in Andhra Pradesh, YSR Congress Party president Y.S. Jaganmohan Reddy retained his Kadapa Lok Sabha constituency and his mother Vijayamma the Pulivendula Assembly constituency with record-breaking margins.

In the by-election results announced on Friday, Mr. Jaganmohan Reddy secured 6.9 lakh votes, more than 65 per cent of the total votes polled. He won with a majority of 5.45 lakh votes over his nearest rival, Health Minister D.L. Ravindra Reddy, who secured 1.46 lakh votes. Telugu Desam Party (TDP) nominee M.V. Mysoora Reddy came third with 1.29 lakh votes. Both his rivals and 39 independents forfeited their deposits.

In Pulivendula, Ms. Vijayamma secured a record 85,191 votes margin, surpassing her husband's 68,681 vote margin in the 2009 elections. She humbled her nearest Congress rival and brother-in-law Y.S. Vivekananda Reddy, who got a little more than 28,000 votes.

TDP candidate M. Ravindranath Reddy, with 12,000 votes, remained a distant third. The nominees of these parties and 22 independents could not retain their deposits.

The emphatic victory of Mr. Jaganmohan Reddy is a huge setback not just to the Congress, but the TDP as well, as both had left no stone unturned to contain Mr. Jaganmohan Reddy. It is seen as a personal triumph for the 37-year-old leader, who made it “a battle between Congress president Sonia Gandhi and self-respect of the people of Kadapa.” He claimed the verdict was a pointer to the political changes in the offing.

Mr. Jaganmohan Reddy bettered the 4.2 lakh vote margin registered by his father from the same Kadapa seat in 1991.

His winning margin was next only to that of the former Prime Minister, P. V. Narasimha Rao, who won with a 5.8 lakh vote margin from Nandyal.

Chief Minister N. Kiran Kumar Reddy's strategy to deploy as many as 20 Ministers in the two constituencies and the TDP's aggressive campaign on alleged corruption could not stem the tide.

Mr. Kiran Kumar Reddy as well as Andhra Pradesh Congress Committee president D. Srinivas conceded that there was a strong sentiment in Mr. Jaganmohan Reddy's favour.