By FOX Sports staff
BVB got their campaign up and running last month when they beat Bayern Munich 4-2 to claim the DFL Supercup, before cruising to a 3-0 win over Wilhelmshaven on Saturday to progress to the second round of the DFB-Pokal.
The victories mean Jurgen Klopp's men head into their Bundesliga season opener against Augsburg high on confidence, but Sahin believes there is still room for improvement.
"We're heading very much in the right direction," he said on the Bundesliga's official website.
"I'm looking forward to everything, to every competition.
"We hit a good run of form at the end of last season but we need to become even more effective - conceding fewer goals and in the best case scenario, scoring more as well."
Sahin, who began his career with Dortmund, returned to the Signal Iduna Park in January on loan from Real Madrid after failing to establish himself with Los Blancos and a disappointing spell at Liverpool.