Ulster's must-win clash with Glasgow at Ravenhill will be the first of 11 Heineken Cup round five matches broadcast live on Sky Sports.
The Irish province saw their unbeaten start to the season ended by Northampton last weekend and need to bounce back against the winless Warriors to stay in control of Pool 4.
That actions gets underway at 8pm on Friday, 11 January, with Northampton's home date with Castres available on the red button.
The Saints looked dead and buried after the 26-5 hiding by Ulster at Franklin's Gardens in round three, but their one-point victory in the return fixture means victory over the French side will keep them in the hunt.
Saturday's action sees Harlequins host Connacht at the Stoop (1.35pm), where victory will confirm top spot in Pool 3, while fellow unbeaten side Toulon face Cardiff at the same time on the red button.
Saracens travel to Racing Metro (3.45pm) knowing victory puts them within touching distance of a home quarter-final, which is followed by Leinster's must-win meeting with Scarlets (6pm).
The back-to-back champions are on the brink of losing their crown after successive defeats, and will be hoping Exeter do them a favour by breaking Clermont's 51-game unbeaten record at the Stade Marcel Michelin.
Sunday sees Munster travel to Edinburgh (12.45pm) in dire need of a victory, and the weekend culminates with the Toulouse-conquering Ospreys hosting Leicester (3pm).
Heineken Cup round five: Live on Sky Sports
11 January: Ulster v Glasgow, Northampton v Castres, both 8pm.
12 January: Harlequins v Connacht, Zebre v Biarritz, Toulon v Cardiff, all 1.35pm; Racing Metro v Saracens, 3.40pm; Leinster v Scarlets, Clermont v Exeter, both 6pm.
13 January: Edinburgh v Munster, 12.45pm; Ospreys v Leicester, Toulouse v Treviso, both 3pm.