Group G is one of the more convoluted pools heading into the final round of Champions League fixtures.
Zenit will go through with a win away to Benfica and Lyon do not beat Leipzig, or if both games are drawn due to their head-to-head superiority over Lyon, or regardless if Lyon lose.
Benfica only have a place in the Europa League to play for, and even that is a far from simple objective to achieve.
The Portuguese side will do so if they win by a scoreline better than 3-1 and Lyon do not lose, or if they win by any score and Lyon lose to Leipzig.
With so much at stake already on matchday 6, here's how to follow all the action on Tuesday night...
TV channel and live stream information
The match will be televised live on BT Sport 1 and can be streamed live online via the BT app and website, with kick-off scheduled for 8pm GMT.
You can follow all the action and analysis on Standard Sport's LIVE blog.
Prediction: Zenit 2-0 Benfica
Zenit won 3-1 in St Petersburg back in October, and should be triumphant again on Tuesday night.
Team news
Benfica: Vlachodimos, Tomas Tavares, Ferro, Dias, Grimaldo, Pizzi, Pires, Taarabt, Cervi, Chiquinho, Vinicius
Subs: Caio, Seferovic, Samaris, Jardel, Nuno Tavares, Zlobin, Jota
Zenit St Petersburg: Kerzhakov, Karavaev, Osorio, Ivanovic, Douglas Santos, Barrios, Ozdoev, Shatov, Erokhin, Azmoun, Dzyuba
Subs: Smolnikov, Mak, Kranevitter, Musaev, Vasyutin, Vorobjov, Sutormin
Referee: Antonio Miguel Mateu Lahoz
