19-year-old Lena clinched her country's first victory in the competition since 1982 with 'Satellite', produced by Julie Frost.
Turkey, represented by maNga, were runners-up with 170 points. Romania's Paula Seling & Ovi and Denmark's Chanée & N'evergreen followed in third and fourth place respectively.
Meanwhile, the UK's entrant Josh Dubovie finished in last place with a song penned by Pete Waterman, scoring just ten points, falling victim to Georgia, who gave Belarus the maximum 12 points at the last minute.
Dubovie's finish was worse than Andy Abraham's in the 2008 contest, which veteran Eurovision commentator Sir Terry Wogan cited as one of his reasons for quitting.