Ricciardo's Renault engine gave up the ghost mid-session, spraying oil onto the track and onto the visor of Pierre Gasly, who was circulating close behind at the time of the failure.
A PU change will be made before FP2, but Ricciardo is not expected to serve a penalty.
The session ended with Vettel spinning backwards into the barriers in the last sector. Vettel hit the wall rear-end first, which will raise fears of the need for a new gearbox.
Hamilton also reported losses of power in the session and his Mercedes went into limp mode at one point. His team-mate Bottas will start Sunday's race from the back of the grid, despite showing good pace here, as he has taken a new engine for the season-finale.