But the 2012 finalists will also have an eye on creating a bit of tournament history for themselves by winning a Heineken Cup match on French soil.
The Province has never won a Heineken Cup game in France, but did record a victory on French soil in a pre-season friendly in August with a 20-15 win over Bayonne.
Ulster beat Castres 41-17 in their opening Heineken Cup Pool 4 game at Ravenhill in October but Mark Anscombe's team will face a formidable challenge as Castres Olympique have won three of their past four home matches in the competition.
Ulster are sweating on full back Jared Payne, who has an ongoing groin complaint, and his fitness will be monitored throughout the week.
Payne scored a 73rd minute try in the 23-6 Round 5 win over Glasgow Warriors that booked their place in the last eight and has been an ever-present during this season's campaign, also crossing against Northampton Saints at Franklin's Gardens.