With over 90 percent of the votes counted, the National Election Council said Noboa had an unassailable 12-point lead over his leftist rival Luisa Gonzalez.
Official results showed Noboa with 56 percent of the vote, against Gonzalez’s 44 percent – a far bigger winning margin than expected after a virtual tie in the first round.
Speaking to jubilant supporters in his hometown of Olon, the 37-year-old president claimed a “historic victory”.
“A huge hug to all those Ecuadorians who always believed in this young president!” he said.
“Ecuadorians have spoken, from tomorrow morning we will go to work.”
Gonzalez – seemingly shocked by her weak showing and perhaps the end of her dream of becoming Ecuador’s first woman president – immediately questioned the results.
She accused Noboa of “the most grotesque electoral fraud” and called for a recount of the ballots.
“I refuse to believe that the people prefer lies over the truth,” she said.
She did not immediately provide evidence for her claims of fraud. (AFP)