On the night of the final Cinquetti performed 12th in the running order, following Portugal and preceding Yugoslavia. As with all performances from 1964, only an audio recording of Cinquetti's contest performance is known to survive (although footage of sections of her winning reprise has resurfaced). Audiences in the auditorium at this period were traditionally restrained and respectful, rewarding each performance with the same amount of polite applause. However, the recording captures an unprecedented audience response to a Eurovision song, with loud and sustained cheering alongside thunderous applause. Each national jury awarded 5-3-1 to their top 3 songs, and there was no doubt from the start of the voting that "Non ho l'età" was the winner. Of the other 15 national juries, eight (Austria, Belgium, Finland, Luxembourg, the Netherlands, Portugal, the United Kingdom and Yugoslavia) placed the song first, with three others (Germany, Monaco and Switzerland) ranking it second. At the close of the voting "Non ho l'età" had received 49 points, winning the contest by an enormous margin over runners-up the United Kingdom, who had amassed only 17 points. In terms of points received by the winner in relation to the runner-up, it is the most comprehensive victory in Eurovision history.
"Non ho l'età" went on to become a major hit across Europe. The BBC had taken the unusual step of re-broadcasting Cinquetti's winning reprise on the day after the contest in response to the volume of calls from viewers asking for another chance to see the performance, and the song became a top 20 hit at a time when almost all non-British music had been pushed off the UK Singles Chart by the explosion of home-grown talent. The song has retained its reputation and is generally considered one of the best Eurovision winners of all.