Barcelona can wrap up a difficult UEFA Champions League group early with a win in their next match. Barça have 9 points, while their rivals, Inter Milan, have 6. Barça would go to 12 with a win, leaving the Italians stuck on 6. With only two games left afterwards, Inter could only at best tie the points total (12) with two wins, assuming Barcelona lose both matches. The first tiebreaker in case of two teams having the same amount points is a direct matchup, which Barcelona at that point would own, having beaten Inter in both games.
Tottenham Hotspur and PSV Eindhoven have just a point each, meaning even winning all three remaining matches would only take them to 10. Thus, Barcelona would win the group with two games left to spare if they can defeat Internazionale tomorrow.
Even a draw would be enough to guarantee qualification, although not necessarily as group winners. Barcelona would go to 10 points. Inter could reach as much as 13 points (11 with one draw), but that would mean Tottenham or PSV could only go up to 7 (or 8), since one of those wins would be against one of those two. Inter would go through as group winners with 13 or 11, Barcelona would be second with 10.
There exists another scenario in which Inter gets to 10 points by winning one game and losing the next after a hypothetical draw against Barça. Spurs or the Dutch team (but not both at the same time) could also reach 10 points, by winning all three of their remaining games. However, with all of Barça, Inter, and either Spurs or PSV on 10 points, Barcelona would still own the tiebreaker over the other two teams. They would be the group winners, with Spurs or PSV getting by as second in the group. This tiebreaker is points among matches involving tied teams. Barcelona would have two wins and a draw, PSV or Spurs would have two wins, and Inter would have a win and a draw.
To simplify matters, Barcelona are in a very good position and could consolidate their advantage way ahead of schedule, even with Lionel Messi limited by injury.