The team has 39 points heading into Monday's free skates in the other three disciplines.
Following the Russian Olympic Committee's suspension, the Olympic Athletes from Russia are competing at the Games in PyeongChang under the Olympic flag.
With Zagitova lying in wait next week it was vital Medvedeva produced something special to lay down a marker - and she didn't disappoint.
Two-time world champion Medvedeva, who had returned from an enforced injury-marred break, said she was pleased with her performance in the Russian capital, taking into account the fact she was forced to skip several tournaments while recovering from a fractured foot.
The 81.06 - it actually seemed a bit low for such an overwhelming routine - easily beat the field, lifting her team into second place with 31 points.
Medvedeva's mesmerizing short program Sunday nearly made everything else seem ordinary.
When Medvedeva stepped onto the ice for her Olympic debut her team were lagging well behind after an assured display from Canadian ice dance stars Tessa Virtue and Scott Moir. The duo who won ice dance gold at Vancouver in 2010 were competing after acting as Canada's flagbearers at the Pyeongchang Games opening ceremony.
Soviet and Russian figure skaters have traditionally dominated pairs events since 1964, when Ludmila Belousova and Oleg Protopopov claimed the first gold for the USSR at the Innsbruck Games. The silver was brought home by Evgenia Medvedeva and Alina Zagitova (ladies' single skating), Mikhail Kolyada (men's single skating), Ekaterina Bobrova and Dmitri Soloviev (ice dance), and Natalia Zabiiako and Alexander Enbert (pair skating).
Trump not looking to replace Kelly, aides say
The White House response serves as a high-profile illustration of the obstacles many women face in speaking out about their abuse. No action was taken to remove him from the staff, and instead, Kelly and others oversaw an elevation in Porter's standing.