After defeat in
Marseille goalkeeper Steve Mandanda was immediately on alert as he made a fine save to keep out Reus's 20-yard drive but there was little he could do about Lewandowski's goal.
It came after a perfectly executed counter-attack, which saw Dortmund outnumber the Marseille defence six players to three.
It was therefore a matter of the home side quickly recycling the ball between themselves, effectively pulling apart the defence, before fullback
Marseille's response was for
Langerak, uncapped by his country, took his place between the posts after
Instead, Dortmund pressed for a clear advantage with
Lewandowski last week confirmed he would leave for Bayern Munich but - after a double in the weekend win over Freiburg - was again proving his full commitment to the cause as he created more space before firing over.
Dortmund had to wait until five minutes after half-time to go 2-0 up when Mandanda made a hash of Reus's 30-yard free-kick.
The OM goalkeeper expected
Marseille, third in Ligue 1, began to unravel and Nicolas N'Koulou gave away a clear penalty when he dived in on Reus.
Lewandowski converted the 80th-minute spot-kick down the middle, for his fourth goal in two games since confirming his exit, to seal an easy night.