Leading 1-0 from the first leg in Portugal, Benfica were under the cosh from the off and hot-shot Aubameyang needed just four minutes to head the home side in front.
The second half was all Dortmund and after missing several chances they made the breakthrough when Christian Pulisic scored just before the hour.
Two minutes later it was 3-0 on the night and tie over, Aubameyang prodding in from close range to send Dortmund into the last eight, where they join fellow Germans Bayern Munich.
The Gabon striker sealed his hat-trick with another close-range finish five minutes from time.
afp

