The SDLP has elected Margaret Ritchie as its new leader, after Mark Durkan stepped down following eight years in the post.
The South Down Assembly member beat South Belfast MP Alasdair McDonnell by 222 votes to 187 in the contest to replace outgoing Mark Durkan at the head of the nationalist party.
Ms Ritchie's victory was met with a rapturous reception from the conference floor, with delegates giving the 51-year-old a prolonged standing ovation.
When a degree of order was restored, the party's sole minister in the power-sharing executive made a bold pledge to revive the SDLP's flagging fortunes and make it the largest party in Northern Ireland.
"Together we can do this," she vowed.
"We can put our party back on top and for the sake of the people of the North we must put our party back on top."
Noting that she had risen from a local councillor to party leader in three short years she assured members she was not satisfied yet.
"You may ask if there's no end to this woman's ambition?" she said.
"Well there is - I want our party to rise again and I want to become First Minister."
She paid tribute to Mr McDonnell and urged the party to get behind the efforts to ensure he retained his South Belfast parliamentary seat.
"I know Alasdair is going to retain South Belfast and everyone of us must put our shoulder to thewheel to ensure that happens," she added.
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The losing candidate wished Ms Ritchie well in her new role and pledged to support her as she led the party into the future.
"Today's Margaret's day and I want to wish Margaret every success in her efforts to move this great party forward," he said.
Mr McDonnell, 60, had vowed to undertake a radical internal shake-up of the party if he had won.
He said it was clear the majority of the party had felt his proposals too radical or unnecessary.
"I hold firm in my conviction that we need to professionalise ourselves and move forward," he added.
On Saturday Mr Durkan used an emotional farewell speech to colleagues to insist that while his party was central to ending the Troubles, it remained vital to building a new future for all.
He said the power-sharing government was being mismanaged by the DUP and Sinn Fein, while the scandal over MPs expenses eroded public confidence in politicians.
The former finance minister in the Stormont Executive and MP and MLA for Foyle is quitting to concentrate on his role at Westminster
Irish Taoiseach Brian Cowen sent his warmest congratulations to Ms Ritchie on her election success.
"In assuming the office of SDLP leader, she follows in one of the most distinguished lines in Irish political history," said Mr Cowen.
"I am sure she will continue that proud tradition into the future."
On Saturday night the Taoiseach attended the SDLP conference where he paid tribute to the party's outgoing leader.
Two years ago Ireland's ruling party decided to organise in Northern Ireland.
Fianna Fail also flirted with a potential link up with the SDLP, but an alliance never materialised.
Northern Ireland Secretary Shaun Woodward has also congratulated Margaret Ritchie on becoming leader of the SDLP and paid tribute to out-going leader, Mark Durkan.
"As a result of the Hillsborough Castle Agreement, Northern Ireland is entering a new era which could see the whole community move forward together in a way not possible before," he said.
"But like the Good Friday Agreement and the St Andrews Agreement, what was agreed on Friday is not an end in itself.
"There will be challenges ahead - but under the leadership of Margaret I have no doubt the SDLP will play its part in ensuring that the promise of political stability, social and economic advance and the creation of a genuinely shared future is realised."
Sinn Fein President Gerry Adams also expressed his congratulations to the new SDLP leader.
"I wish Margaret Ritchie well in her difficult job, and I hope that this will usher in new era of constructive and forward looking politics from the SDLP," he said.
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