Kostornaia held onto her short-program lead despite a fall in the free skate, scoring a total 240.81 points, enough to beat 15-year-old Anna Shcherbakova by 3.05. Another 15-year-old Russian, Alexandra Trusova, took bronze on 225.34.
Russia won the ice dance earlier Saturday with Victoria Sinitsina and Nikita Katsalapov, following victory in the men's event for Dmitri Aliev on Thursday and in the pairs for Alexandra Boikova and Dmitry Kozlovsky.
The feat of winning all four European championship events was last achieved by Russia in 2006, when all-time greats Evgeni Plushenko and Irina Slutskaya were skating. The women's competition underlined just how far ahead Russia is.
All of the top three are coached by Eteri Tutberidze, who has revolutionized skating with her emphasis on athleticism - including making her skaters the first to regularly attempt multiple quadruple jumps - and an intense focus on developing skaters in their early teens.
Kostornaia landed seven of eight triple jumps in her free skate, including two triple axels. She remains unbeaten in international competitions since moving up to senior level this season. Shcherbakova and Trusova both jumped quads, with the extra points of difficulty making up for some inconsistent landings.
Shcherbakova landed two quads, one of them under-rotated, and fell on a third. Trusova had planned five quads in her “Game of Thrones”-themed free skate but ended up attempting three and landing one. None of the others came close. The U.S.-born skater Alexia Paganini took fourth place for Switzerland, a full 32 points off the bronze spot.
Russia has now won the last seven women's titles at the European championships with six different skaters, underlining the explosive but generally short careers of Russia's champions. Showing the depth of talent, last year's European champion Sofia Samodurova placed just ninth last month at the highly competitive Russian national championships.
In ice dance, it's been a different story. Russia's win was a surprise after a run of five titles for France's Gabriella Papadakis and Guillaume Cizeron. Sinitsina and Katsalapov scored 220.42 points to beat Papadakis and Cizeron by 0.14 despite having started Saturday's free dance in second place.
That made them the first dancers to beat the French duo since Canada's Tessa Virtue and Scott Moir took the gold medal at the Winter Olympics in 2018. The ice dance bronze went to another Russian duo, Alexandra Stepanova and Ivan Bukin, on 211.29. They had been fourth after the rhythm dance but overtook Italians Charlene Guignard and Marco Fabbri in Saturday's free dance.
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