Independent Peter Law has claimed there was "brute force and thuggery" in the run-up to his dramatic victory over Labour in Blaenau Gwent.
Peter Law greets supporters in Blaenau Gwent after his victory
He said his result was "what you get when you don't listen to people."
Mr Law produced by far the most startling result of election night in Wales by overturning Labour's 19,000 majority in its valleys heartland.
The former Labour Welsh assembly member left the party in protest at all-women shortlists used to pick its candidate.
'People rose up'
Labour Party workers admitted his "crushing victory" well before the declaration, and the concession came before candidate Maggie Jones even arrived at the count.
In contrast, a buoyant Mr Law chatted to members of the media and waved at supporters at Ebbw Vale leisure centre as the ballot papers were counted.
Maggie Jones said she was 'shocked' at the scale of defeat
Before the declaration Mr Law said Welsh Secretary Peter Hain and First Minister Rhodri Morgan should "hang their heads in shame".
After the announcement, he said: "The people rose up because their integrity was being compromised by New Labour.
"It became a crusade and people wanted their dignity and self-respect to be recognised."
Mr Law almost had to withdraw from the contest a month ago when he discovered he had a brain tumour the day before he was due to announce his candidature.
He underwent surgery just after, but decided to press ahead and stand.
Mr Law said he was confident his health would not prevent him doing both jobs as MP and AM.
Asked how he would cope as an independent MP, he said: "No-one's going to intimidate me. We've seen brute force and thuggery up here already and we are not having any more of that."
Labour won 72% of the vote in this valleys seat in 2001, and retiring MP Llew Smith - who was also opposed to all-women shortlists - had earlier predicted that Mr Law would win.
Speaking after the count, he said he was not surprised at the result.
"I have been telling everyone who has been willing to listen now for the last couple of years that if New Labour did go forward with the all-women shortlists and in reality parachute a candidate into Blaenau Gwent, then the seat would be lost and would be lost in a big way," he said.
Still bearing the scars of his recent surgery but looking relaxed and happy at the count, Mr Law said he had no regrets about his position.
Peter Law is congratulated by Conservative Phillip Lee
Before the result was announced, the confidence of Mr Law's followers contrasted with the mood of Labour, whose party workers and supporters stood in small huddles, bracing themselves for the heavy defeat they now knew was inevitable.
After the crushing 9,000 -majority victory was announced, Mr Law began his emotional acceptance speech: "It's a very good morning in Blaenau Gwent. This is what you get when you don't listen to people."
He added: "It's been a great victory for the people of Blaenau Gwent because they are standing up and saying our integrity is worth far more than it has been judged to be.
"It was not about men and women it was about the right of choice."
Mr Law's wife Trish wept throughout his speech
Afterwards she said: "I was so proud of him but I felt sad that it had come to this. If things had been done differently Peter would have supported the Labour candidate to the hilt."
In her speech, Maggie Jones said Labour would return to claim the Blaenau Gwent constituency.
But after saying that the people of Blaenau Gwent "deserved the best," the end of Ms Jones' speech was drowned out by Mr Law's supporters' cries of "we've got the best".
Speaking afterwards, Ms Jones admitted that she was "shocked" by the scale of her defeat.
She added Labour "under estimated the level of sympathy Peter was getting" but said she had not believed defeat was likely until the final moments of the campaign.
Ms Jones said she would have to "reflect" on whether to stand again but said she regretted Blaenau Gwent "now has a part-time MP."
Mr Law's supporters said his victory had been worth the infighting that had erupted in the local Labour Party over the issue of all-woman shortlists.
Delwyn Davies said: "We had no doubts he would win, but I was surprised at the majority. He was up against a party machine."
Fellow Law supporter Andrew Finney said: "They love Peter here. In Abertillery he's like the Pied Piper.
"When Peter had his illness, people in Abertillery were crying but when they saw him later they mobbed him."