The 47-state Human Rights Council, which is holding its first special session on Darfur, approved a consensus proposal on Wednesday that left the naming of the five "highly qualified" team members up to the council chairman.
Vesa Himanen, Finland's ambassador, said on behalf of the EU following the decision: "I think that we can be proud of this result."
Kofi Annan, the outgoing UN secretary-general, told the opening session on Tuesday that the council must help end the "nightmare" of violence by sending a "clear and united message ... that the current situation is simply unacceptable".
The council, launched in June as part of UN reform, was under pressure to show it can act effectively on Darfur where aid officials say more than 200,000 have died in violence over the past three years.
After two days of tough haggling over membership of the mission, it was agreed that Luis Alfonso de Alba, the council chairman and Mexican ambassador to the council, should name the team and that it would be accompanied by Sima Samar, the UN special investigator for Sudan.
The EU and its allies had feared that an initial African call for the team to be made up of council ambassadors would have left it without the authority to carry out an investigation and produce clear recommendations.
Khartoum and its backers on the council, brushing aside reports from Annan and other top officials, say the situation in Darfur, where long-simmering ethnic violence erupted into war in 2003, has improved since a peace treaty earlier this year with one leading rebel group.
It also disputes the death toll in the region, where over 2 million have been driven from their homes, and pins the blame for rights' violations on rebel groups that are still fighting.
Western diplomats say there is already abundant information available about what is happening in Darfur and the main point of a mission is to increase international pressure on Khartoum to accept UN peacekeepers in the region.