Goals from Lukasz Piszczek and Marco Reus handed Borussia Dortmund a 2-0 victory over Porto in the first leg of their Europa League last-32 tie.
Piszczek put the hosts on the way to a comfortable victory after just six minutes at Signal Iduna Park, before Reus made the result certain 19 minutes from time.
The Bundesliga side fully deserved their victory but they may yet rue wasting a number of chances to completely put the tie out of Porto's reach.
The hosts started brightly and were immediately rewarded as Piszczek headed home from close range after Iker Casillas had kept out his initial effort.
Dortmund continued to control possession but did not further threaten Casillas' goal in the first half, with Reus firing a free-kick well over and Marcel Schmelzer shooting into the side-netting from a tight angle.
Shinji Kagawa also failed to hit the target after a bright move, while Porto's best chance of the first period saw Sergio Oliveira shoot straight at Roman Burki.
The match became more physical in the second half with some heavy challenges coming in from both sides, but Dortmund retained control and patiently waited to create chances.
Kagawa, Piszczek and Schmelzer all went close before Reus doubled the lead. The goal came after Kagawa shrugged off a defender then fed Henrikh Mkhitaryan, whose first-time lay-off was neatly clipped home by Reus.
Kagawa then shot narrowly wide and Mkhitaryan hit the woodwork with a powerful header as Dortmund maintained the pressure, but Porto had a late chance as substitute Suk Hyun-jun had a shot blocked by Burki.