Fils held a 3-2 lead in the first set, but Medvedev dominated the rest of the way. Overall, Medvedev won 28 of 31 first-service points while collecting 16 winners against just three unforced errors.
Number two seed Jannik Sinner of Italy, Croatian wild-card entrant Borna Gojo and France's Gael Monfils, who is playing on a protected ranking, also blanked their respective opponents in first-round matches. Sinner topped American Ben Shelton 7-6 (2), 7-5; Gojo ousted Russia's Aslan Karatsev 6-3, 6-3; and Monfils downed Daniel Altmaier of Germany 6-4, 6-4.
In second-round action, fifth-seeded German Alexander Zverev downed Great Britain's Cameron Norrie 6-2, 6-4, while Number eight seed Karen Khachanov of Russia defeated the Czech Republic's Jiri Lehecka.
Swiss Indoors Basel
Argentina's Tomas Martin Etcheverry rallied to beat Andy Murray of Great Britain 6-7 (5), 6-3, 6-2 in a second-round match at Basel, Switzerland.
Etcheverry connected on 71 percent of his first serves and saved five of six break points en route to the comeback. Murray lost his serve to open the third set and was never able to recover.
Number four seed Hurbert Hurkacz of Poland also won his second-round match, sweeping German Jan-Lennard Struff 6-1, 6-4.
Second-seeded Norwegian Casper Ruud, third-seeded American Taylor Fritz, sixth-seeded Canadian Felix Auger-Aliassime and France's Ugo Humbert prevailed in first-round matches.
