The Milram sprinter beat Graeme Brown at the end of a 200km stage into Duderstadt.
He holds a 14 second lead over the Rabobank rider entering Sunday's final stage as he looks to defend his title.
Caisse d'Epargne's Vladimir Karpets won stage two of the Vuelta Ciclista a la Rioja in Casalarreina.
Movistar confirm departure of Miguel Angel Lopez
18/09/2021 AT 12:12
Team-mate Ruben Plaza was second and leads on general classification after the duo finished 53 seconds clear on a stage that featured three major climbs.
Vuelta a España
'We’re humans, not machines' – Lopez says sorry for quitting
04/09/2021 AT 20:50
Vuelta a España
Lopez 'spat the dummy like a spoilt child' by quitting with 20km to go
04/09/2021 AT 19:00