Vienna needed only an away goal to regain the advantage and introduced 6ft 7in striker Stefan Maierhofer, who soon had the ball in the net but saw his effort ruled out for a foul on keeper Bradley Guzan.
But City let the visitors back into the game within a minute as centre back Stefan Savic failed to deal with a long ball and Jermain Defoe took the ball round City goalkeeper Joe Hart to finish into an empty net.
Jupp Heynckes' side continued to press after the half-time break when Stefan Kiessling saw his shot from the left tipped over the bar by Drobny while Ramos had the ball in the net again for the home side but the effort was chalked off after the assistant referee flagged for offside.