Stade Français Paris lead Worcester Warriors by four points. Warriors must win and deny Stade anything to bring the equation down to tries or aggregate points in their two games, or they must win with a try bonus point and once again deny Stade a losing bonus.
Pool 2 - Toulon or Newcastle Falcons
Toulon have a two point advantage over Falcons and lead them in the head-to-head. Toulon host Petrarca Rugby in Round 6 and Falcons travel to Lyon. A Toulon win will be enough to secure the Pool winners spot, as will be a draw if Falcons don't earn a bonus point victory in Lyon.
Pool 3 - London Wasps or Bayonne
London Wasps lead by two points from Bayonne, but are down 2-1 on tries in the head-to-head. That means they need to beat Bordeaux-Begles at home in Round 6 to guarantee a quarter-final place. Bayonne host Rovigo and can go through with a draw or a win, as long as Wasps fail to earn any points.
Pool 4 - Exeter Chiefs or Perpignan
Exeter Chiefs are one point ahead of Perpignan and have a precious losing bonus point from their game there in France in Round 1. They host the French side in a winner-takes-all clash at Sandy Park.
Pool 5 - Brive or Sale Sharks
Brive head to Edgeley Park on Thursday night knowing they need to get at least a losing bonus point to top the Pool. A win or draw will send them into the last eight, while two-time winners the Sharks need to go for broke and win without conceding a bonus point to overcome the three point gap at the top.