The Reds are second behind Atletico Madrid going into their final match in this stage.
They take on PSV Eindhoven tomorrow with their place in the last 16 already secured. But Benitez is already thinking about the draw and the knockout stages.
He revealed: "It is difficult to know whether you want to finish first or second.
"We cannot play an English side in the last 16, so that reduces the options.
"It is also possible to face Lyon or Bayern Munich so it is very difficult to decide who you'd rather play next.
"But the best thing about winning the group is that you play the second leg of the next round at Anfield, which is very important for us."