The Germany international hailed the approach his team had against Thomas Schaaf's men, as they ran riot at Weserstadion to climb up the league table
The 23-year-old opened the floodgates against the hosts with a thunderous free-kick, before Mario Gotze, Felipe Santana, Robert Lewandowski and Jakub Blaszczykowski completed the rout for the German champions.
"The team came to a consensus at half-time that a 2-0 lead was not enough," Reus told reporters after the match.
"Despite the cold, we played a great match and rightly won. We were completely focused for all 90 minutes.
"I am glad I was able to score from a free-kick again, after practising so much in training."
Reus rejoined his boyhood club for €17.1 million this summer, after impressing with Germany at Euro 2012.