However, just four minutes later he did have his goal. It was a defensive error from Oliver Kirch, who passed straight to the Stuttgart man for him to fire in low for 1-0.
Right on the half-hour mark Dortmund got themselves back in the game through Reus, who found space to latch onto Jonas Hofmann's pass and clip into the far corner.
In the second half Dortmund came out strongly and could have levelled it on 55 minutes, but Robert Lewandowski struck a powerful effort against the woodwork.
However, they did not have to wait too much longer. Georg Niedermeier brought down Lewandowski when the Pole was through on goal and got himself sent off, with Reus calmly converting from the spot for 2-2.
A man up and level, there was to be a late winner for Dortmund. It was Reus with his hat-trick, but his strike took a wicket deflection on its way past Sven Ulreich.