When asked by The Associated Press if he thought the weekend by-elections were free and fair, President Thein Sein said through an interpreter: "It was conducted in a very successful manner."
Thein Sein's brief remark was also the first comment by a top government official since the election took place on Sunday. He spoke on the sidelines of a summit of Southeast Asian countries in Cambodia.
The weekend vote in Myanmar was called to fill just 45 vacant seats in the country's 664-seat Parliament, but took on historic significance because of Suu Kyi's presence. After two decades as a political prisoner, Suu Kyi's victory marked a turning point in her political career and for the country as it emerges from a half-century of military rule.
The Election Commission confirmed Monday that Suu Kyi's National League for Democracy had swept 40 of the 45 seats at stake, with results from far-flung constituencies not yet reported.
The NLD's own count gave it 43 seats, with just one loss in the distant Shan state to an ethnic Shan party candidate, a party official Soe Win said Tuesday. The NLD failed to contest one constituency after its candidate was disqualified.
Suu Kyi kept a low profile on Tuesday after a jubilant victory speech a day earlier outside her party headquarters, where thousands of supporters crowded the streets to see her.
"We hope this will be the beginning of a new era," a beaming Suu Kyi told the crowd.
She called her victory "a triumph of the people who have decided that they have to be involved in the political process in this country."