Despite two attempts running with a fresh set of the quickest soft tyres late into the hour at the Austin track, two-time champion Verstappen was unable to depose the Ferrari of Sainz.
That left the Spaniard to sit pretty by 0.22 seconds as Scuderia team-mate Charles Leclerc did not contest the session to make room for F1 rookie and 2019 FIA F3 champion Robert Shwartzman.
