The former New Zealand prime minister, who faced more questions than any other candidate, rejected suggestions that she was a household name. "I have never been an establishment candidate for anything," she said.
"I have come from the outside of everything I have done, from a rural background to urban settings, as a woman breaking into a man's world, which was politics in my country, as a woman becoming the first elected Prime Minister, the first woman appointed Administrator of the UNDP [UN Development Programme].
"I don't think in all honesty anyone could see me as an establishment candidate because I've come from out of the box and I'll always be a bit out of the box in looking at how to, in my work, create a ladder of opportunity for others to be included and to have a fair go based on their abilities."
It was her most lively answer to dozens of questions, most of which covered her views on the work of the UN, her leadership style, how to improve and reform it, diversity, and how to prevent conflict.
Miss Clark was the eighth of nine declared candidates put through their paces this week by members states in a new open process to replace Ban Ki-moon whose term expires in December. The decision will be made by the General Assembly on the recommendation of the Security Council.
i am all in for my awe-inspiring fellow countrywoman helen clark - she'd make an incredible UN Secretary General #Helen4SG !!!!!
— Lorde (@lorde) April 14, 2016
Miss Clark began this morning's session by making a personal statement about her background and her values.
"I grew up on a backcountry farm on an unsealed road in New Zealand and I learnt from my parents values which I think are essential to leadership.
"They are about being ambitious but realistic, about being hardworking and resilient when the times get tough.
"Many in my family and my local community fought and were killed in World Wars 1 or 2 and so like other New Zealanders of my generation I was brought up to have deep respect for the United Nations."
Throughout her life she had done her best to find ways to overcome inequality and injustice wherever she had encountered them. The first cause she had become actively involved in as a young person was against apartheid in South Africa.
"Its end, to which the UN contributed a great deal, was a major achievement of the late 20th century."
Miss Clark, who was Prime Minister for nine years and has been head of UNDP for seven, said she took a very "holistic approach" to the role of Secretary-General and said the UN "orchestra" had to work together better.
"If we take, for example, the peace and security challenges there is very little that ends up on an agenda of the Security Council that somewhere doesn't point to an underlying deep development deficit.
"And I think this whole great orchestra at the UN has to play together so that we are not always just the firefighters out with the hose when there is a problem but actually we are supporting, advocating for, investing in the long term things which will make for more peaceful and inclusive societies. I very much see the links here."
Asked about whether the term of the Secretary-General should be a single one rather than the traditional two five-year terms, she said she was relaxed about it. She could see the case for having a single non-renewal term, "a one-stint at it and pass the baton on".
That was over to member states to decide what they wanted "but I am relaxed either way".
A single term is promoted by those who believe that having a renewal term makes the Secretary-General's too ready to please the Permanent Five countries on the Security Council, who are able to veto appointments.
'I am very task-focused'
Asked what she thought about regional rotation of the Secretary-General's job - Eastern Europe believes it is its turn - she suggested the job should go to the best person.
"I responded to the invitation from the presidency of the General Assembly and president of the Security Council which went to all member states to put their best candidates forward. I think given the challenges our world faces today, the General Assembly and Security Council should have before them the full range of talent available for the job.
"It's your decision. You make it. That's the spirit in which the New Zealand Government has nominated me."
Referring to her leadership style, she said: "I see myself as a pragmatic, and moderate person, a very task-focused person. I've never been seeking positions for status or glory. I've often found they involved a lot of hard work and not enough family time and too little sleep. But I am very task-focused. I like to get things done. I like to get results. I believe I'm decisive.
"I also think from the background I come from in New Zealand, a highly ethnically and otherwise diverse country, and operating in a diverse region, I know quite a lot from my experience about how to bring people of diverse backgrounds together."
She was asked by a Caribbean country if the UN Secretary-General had a role to play in helping to repair the declining relationship between local banks and international banks which, left unaddressed, could seriously affect local economies.
"I don't pretend to have the answer to that," she said. "But if there is one, I'll try to find it and work the other relevant organisations in the UN common system which includes Bretton Woods institutions to see if there is a way forward."
She said her general view about the role of Secretary-General was "if good offices can be used, they should be used in the interests of international peace, development, and justice".
Miss Clark was also asked by Italy about comments she made on BBC last week in which she said Japan, India, Brazil and Germany were "outstanding obvious candidates to become new permanent members" of the Security Council.
She said Security Council reform was an outstanding matter that had been debated for many years but suggested her reference to new permanent members was in the context of a former position, not one she was promoting now.
"I recall presiding over a cabinet committee on external relations in New Zealand when we debated at great length the national position on this and my response, when the BBC raised the issue, was to refer back to that time and where the debate was centreing around who might be added and on what basis."
She said however that multilateral institutions needed to review their governance "in order to remain relevant, credible and legitimate". "It is important that there is reform which enable the institution or the particular body to look effective."
It was important that reform did not crowd out the ability of small states to be elected to the council. Small state perspectives were needed on the Security Council.
"As Secretary General I would certainly want to move the process forward would study what predecessors had done to encourage reviving the process of discussion to try to get some resolution."
Tough questions
Labour's foreign affairs spokesman David Shearer said the fact Miss Clark was grilled more than other candidates could be down to General Assembly representatives becoming more used to the process as it went on.
"She certainly got some tough questioning...she is seen as a front-runner, and as a front-runner you are going to get more scrutiny than perhaps others will. I think she handled it all really well, I think the way she came across was fine."
Mr Shearer said those in attendance would already be well aware of Miss Clark's view on the need for some reform at the UN.
"She has had a reputation for that sort of thing in UNDP, so everybody in that room would have known what she did with UNDP."
The presentations were important but not critical to the selection process, Mr Shearer said. More important would be the politics behind the decisions of the permanent five members on the Security Council - China, France, Russia, the United Kingdom, and the United States.
"For example, if there is a candidate that Russia is pushing or supporting more than another, it might be a reason for the United States not to back them, and vice versa. In some ways, that provides an opportunity for Helen Clark to be able to weave her way through those big power blocks."
