Borussia Dortmund welcomed back former boss Jurgen Klopp as Liverpool took on Dortmund in the quarter-final of the Europa League.
Liverpool took the lead thanks to the Belgian Divok Origi on 36 minutes.
Hummals caught Liverpool cold heading home on 48 minutes after slack defending from a corner.
Borussia Dortmund 1-1 Liverpool
In the other matches
Ath Bilbao 1 v 2 Sevilla
Villarreal 2 v 1 Sparta Prague
Braga1 v 2 Shaktar Donetsk