Ulster Rugby have qualified for the quarter-finals but they will want to guarantee a home draw by getting an away victory over Castres Olympique.
But to earn that home tie in April they need to do something they have never managed before - win a tournament match on French soil.
The Irish province, who are also top of the PRO12 table, have reached their third successive Heineken Cup quarter-final and were beaten finalists in last season's tournament.
Ulster are the only Irish province to have qualified for the quarter-finals with a game to play, with both Leinster and Munster still needing victories in their final games to have any chance of qualification.
The Belfast side, who won the tournament back in 1999 and rely heavily on Ruan Pienaar, recorded a hard-fought 23-6 victory over Glasgow Warriors at Ravenhill in the last round and will be under no illusions of what faces them in France.
Castres will want to do themselves justice after the manner of their 41-17 defeat they suffered to the Irish province in the opening game of this Pool back at Ravenhill back in October.
The French side suffered a narrow 18-12 defeat to Northampton Saints in their last game in the Pool and cannot qualify for the quarter-finals but they could deny Ulster a home draw in the last eight.
They will be confident that they can make life difficult for Ulster at their formidable home ground of Stade Pierre Antoine, where the Belfast side have never played before.
Match Facts
- Castres' only Heineken Cup Round 6 victory since 2002 came at home to London Wasps (21-15) in 2008/09.
- Castres have won three of their last four home games in the Heineken Cup.
- Ulster have never won in 14 previous visits to France in the Heineken Cup. The closest they came was a 35-all draw in Toulouse on 22 October 2000.
- Ulster boast a tackle completion rate of 92%, a competition-high.
- Castres' scrum success rate lies at 98% after five rounds of competition, comfortably the highest percentage in the Heineken Cup.
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