For the last two years on the senior global level, it's been Evgenia and no one else.
Zagitova, the world junior champion last season, cleanly landed a triple lutz/triple loop combination jump, followed by a triple flip and a double axel.
Medvedeva won the short program in the Olympic team competition last week.
Before Wednesday, the world record for the short program had been set by Medvedeva earlier this year, Medvedeva in 2017, Medvedeva in 2016 and Mao Asada from Japan in 2014.
On paper, Zagitova has more potential points in her programs due to a decision to move all her jumps to the second half of her program. She went on to eclipse the world record set minutes earlier by her rival, earning an astounding 89.92 for first place going into Thursday's free skate.
Medvedeva opened the final group of skaters and displayed a brilliant routine to music by Chopin, flawlessly pulling off all her elements.
"Zhenya and I are friends", Zagitova added, using Medvedeva's nickname. The 31-year-old is twice Zagitova's age and is competing in her fourth Winter Olympics. The U.S. Figure Skating Association banned her for life after her motley crew of hangers-on bashed Nancy Kerrigan's knee in 1994, launching one of the most freakish sports stories ever.
Canada's Kaetlyn Osmond finished third behind the Russian teenagers in the short program.
2017 U.S. Champion Karen Chen put her hand down on her triple lutz jump and wasn't able to execute the triple toe of the planned combination.
Zagitova and Medvedeva are among the 169 athletes cleared to compete on the neutral OAR team at Pyeongchang 2018.
"Evgenia and I are very good off the ice but during the time on the ice and during competitions I personally get this feeling of rivalry".
Five triple loops, just because she could. For her free skate, to Afternoon of a Faun, she may be wearing a spangled green jumpsuit that has already prompted comparisons to Gumby. Have I set a world record? She continues to up her scores. The United States siblings Maia and Alex Shibutani claimed bronze for Team USA.
Speaking after the event, Zagitova said she was nervous going into it and "didn't expect" such a big score. The latter title, which came in January in Moscow, is of particular significance because it marked the first time Medvedeva was beaten in competition since the fall of 2015. Nagasu finished second behind Zagitova in the team event free skate, proving her full point potential is high enough to land on the podium.
Chen made her Olympic debut in the short program, making a mistake on the opening jump but recovering for the rest of the program. Daleman had also struggled with her free program in the fall and elected to go back to her successful Rhapsody in Blue program that helped her take the world bronze medal previous year.
I see four other major contenders. She bounced around the U.S. - Oklahoma City, Ohio, Los Angeles, San Antonio and Las Vegas - eventually serving an apprenticeship under legendary Russian coach Tatiana Tarasova, whose skaters have won eight Olympic gold medals, before returning to Russia.