Zenit is now on 3rd place in Group C in Champions league. But, in their Russian league they offten play with littl number of goals, in that league is played defensivce football. In Champions league in 4 rounds played so far they 3 times went under 2.5 goals.
Benfica is 4th place in Group C. I think that they have some troubles in attack, this seoson in CL they scored only 2 goals. In this 4 games in CL they played 3 games under 2.5 goals.
I expect defensive game with little number of goals.