The endurance of candidates for UN secretary general was tested during grueling two-hour sessions of public hearings in which they were quizzed on their understanding of international affairs and their vision for the UN.
Candidates whose nominations have been publicly announced by their countries faced questions from the wider UN membership for the first time in the organization's 70-year history as part of a push for a more transparent process to elect the next secretary general.
UN member states are aiming to reform the election process in hopes of having more say in the decision, which has traditionally been made by permanent members of the UN Security Council - Britain, China, France, Russia and the US - behind closed doors.
The corridors of the UN are abuzz with assessments of the chances of current nominees and speculations over possible future contenders. German Chancellor Angela Merkel is often mentioned as the dream candidate of many countries.
While former Portuguese prime minister Antonio Guterres and New Zealand's former prime minister Helen Clark are considered the front-runners in the current field of nine candidates, some diplomats say who among them will be the future UN chief is still unclear.
During the hearings, which ended Thursday, Guterres, who served as head of the UN High Commissioner for Refugees until last December, stressed the UN's role in preventing conflicts and terrorism and vowed to deliver a more results-focused organization, if elected.
"I've been given the opportunity to serve in different capacities accumulating a wide range of experiences and this creates an obligation for public service," Guterres said.
The candidate switched between English, French and Spanish with ease, showing his competence different languages - a point on which current Secretary General Ban Ki-moon has been often criticised.
Clark, who is currently the head of the UN Development Programme, said that growing up in New Zealand taught her to be "ambitious, but also realistic" as a leader and promised to make the UN system more collaborative and effective.
"The issue with the UN is not to come forward and say that everything is wrong because not everything is wrong - but there are some things that could be better," Clark said.
"I think we could offer better value for the money to the member states."
Other candidates include Danilo Turk, former president of Slovenia, who said that he would improve the UN's communication with the outside world.
Irina Bokova of Bulgaria, the current director general of UNESCO, said that her candidacy was centered on the importance of diplomacy and upholding human rights, while Vuk Jeremic, a former foreign minister of Serbia, vowed to completely reform the UN.
Vesna Pusic, former Croatian first deputy prime minister and minister of foreign affairs, promised to champion the rights of LGBT people even in defiance of countries' national legislation.
Natalia Gherman, Moldova's former first deputy minister and minister of foreign affairs, said that the next UN secretary general "should be the general of the secretariat and the secretary of the member states" who delivers on promises.
The field also includes Igor Luksic, Montenegro's deputy prime minister and minister of foreign affairs, who at age 39 is the youngest contender, and Srgjan Kerim, former minister of foreign affairs of Macedonia.
Mogens Lykketoft of Denmark, the current president of the UN General Assembly, said that the hearings have already made a difference by establishing "a new standard of transparency and inclusivity" that could influence the outcome of the election.
Civil society organizations also hailed the hearings as groundbreaking.
Yvonne Terlingen, who is part of the 1 For 7 Billion campaign, a global push for transparency in electing the next UN chief, said she was impressed by the hearings.
"We are very happy that [the hearings] are taking place because for the first time ever will all member states be able to form a view about the candidates, know who they are and also know what vision - or lack thereof - they have for the United Nations," Terlingen told dpa.
The increased public scrutiny of candidates is expected to put pressure on council members to pick the most qualified candidate - possibly a woman, after the organization has only had male leaders.
Some countries, most notably Russia, also insist on the next secretary general coming from an Eastern European country, based on the tradition of regional rotation, which explains why seven of the candidates come from the region.
The Security Council is expected to conduct straw polls starting in July and present one candidate to the General Assembly. The next UN chief will take office on January 1 after Ban's tenure comes to an end.