Borussia Dortmund beat Tottenham Hotspur 3-0 in the first leg of their Europa League last eight tie on Thursday.
Gabonese forward, Pierre- Emerick Aubemeyang put the hosts ahead on the half hour mark after a long period of domination.
The reigning African footballer of the year rose highest between two Tottenham centre-backs and planted his header in the bottom corner leaving Hugo Lloris rooted to the spot.
The German side doubled their lead through Marco Reus 29 minutes from time.
Reus grabbed his second and his side third of the evening when he volleyed home following a beautiful cross from Castro.
Spurs who lined up an under strength side with the likes of Harry Kane, Moussa Dembele, Kyle Walker and Erik Lamela dropped to the bench now face a tough task in their bid to make it to the last four of the competition.
They will host the second leg next Thursday at the White Hart Lane.