At the start of the group stages each team could theoretically gain 18 points. The second placed team in that scenario would have 12 points maximum. The third team just 6 points.
Currently we have 4 points, Lazio and Cluj have 3 points and Rennes have just 1pt. By my calculations if we win both legs in the Lazio double header we would have 10 points. Lazio could then only score 9 points total. To do so they have to take maximum points off Cluj and Rennes. If Rennes were to win all their games from now they would have 13 points. The top two qualify. 10 points would probably be enough. 2 more wins out of 4 games is enough. We have two more home matches.
Currently we have 4 points, Lazio and Cluj have 3 points and Rennes have just 1pt. By my calculations if we win both legs in the Lazio double header we would have 10 points. Lazio could then only score 9 points total. To do so they have to take maximum points off Cluj and Rennes. If Rennes were to win all their games from now they would have 13 points. The top two qualify. 10 points would probably be enough. 2 more wins out of 4 games is enough. We have two more home matches.