A 1-0 also gets them through.
BBC's take on it all:
If they win and PSG are beaten at Red Star Belgrade, both Liverpool and Napoli will go through. Both teams will have nine points to PSG's eight, and who finishes top will depend on the result at Anfield.
There are two ways Liverpool can finish above Napoli - with a 1-0 win or with a victory by two goals or more.
A 1-0 win would edge them through on goals scored. That's the simple scenario. This next one is a little more complicated still.
If PSG draw at Red Star and Liverpool win, the Reds, PSG and Napoli will be level on nine points.
They would be separated by their record in matches against each other - essentially a mini three-team group, discounting results against Red Star.
A Liverpool victory on 11 December would see them top that on six points, with PSG and Napoli level on five points.
Who progresses out of those two would depend on Napoli's result at Anfield.
