LONDON — Salvador Sobral of Portugal broke one of Eurovision’s longest-running losing streaks on Saturday night, scooping up the country’s first-ever win with the uncharacteristically somber ballad, “Amar Pelos Dois.”

“I want to say that we live in a world of disposable music, fast food music without any content,” Mr. Sobral said as he accepted his award on Saturday night in Kiev, Ukraine. “Music is not fireworks, music is feeling, so let’s try to really change this, and bring music back.”

Mr. Sobral, 27, performed the song in Portuguese, dressed in an oversized dinner jacket, and often clasped his hands in front of his chest as he sang. It was a far cry from the other performances, which included shirtless men splashing in a pool; a performer wearing a horse head sitting atop a ladder; another straddling a full-sized cannon; and several instances of fireworks.