The 22-year-old’s 87th-minute effort proved mere consolation at the Red Bull Arena as his 10-man side failed to reach the competition’s Round of 16.
He drove past three players before unleashing a left-footed shot past goalkeeper Tolga Zengin after Alvaro Negredo had given the visitors the lead.
A momentary loss of concentration from the Austrians saw them got punished three minutes later by Anderson Talisca.
Despite the loss, RB Lepzig booked a place in the Europa League having finished in the third position behind Besiktas and FC Porto.
The strike Keita’s fourth in the Germans’ colours this term, with two of them coming in the Bundesliga.
