Ms Barton (26), who last year won three aria competitions, including the Otago Daily Times Aria, said she had been feeling more nervous about the prospect of singing in front of fellow graduates than if she had been singing in an aria final.
She sang "Ombra mai fu" from Handel's opera Xerxes at the 3pm ceremony at the Dunedin Town Hall on Saturday.
"It's a song I really love," she said.
Ms Barton (26) already has a BA(Hons) in English and history, and a MusB(Hons), from Otago University.
Having recently completed her Otago studies, she said she was already feeling "a real sense of nostalgia" about the "wonderful time" she had had at the university.
She plans to remain in New Zealand this year, and to head overseas next year to further her musical career.
Ms Barton said she enjoyed the combination of university music research and competitive singing, and her studies had been the fulfilment of hopes she first had in early childhood.
More than 380 graduands in arts, humanities, dentistry, medicine, pharmacy and other health science disciplines graduated in person at the ceremony.
