Dortmund took 4 wins and 1 loss in their last 5 league games as the 3rd team in Bundesliga.
On the other hand, Zenit are the 3rd team in Russia Premier League at the moment. However, they lost their last league game with 2-1, and they lost their first group game with 2-1.
The AH line is home team (-1.50), which is in favor of the hosts.
Therefore Dortmund are expected to win this game easily.