Connacht's 22-14 victory at the Sportsground in Galway, with Dan Parks to the fore, was one of the shocks of the round and put them second behind favourites Harlequins to qualify from the Pool after three games.
The Irish province, who are in only in their second season of the Heineken Cup, have never reached the last eight of this competition but they have already taken the scalps of Quins last season and now Biarritz last weekend.
Biarritz, former Heineken Cup finalists, will want to salvage some pride after their shock defeat to the Irish side when they play in front of their home crowd on Friday evening.
The Top 14 outfit have become the great enigma of the Heineken Cup, proving they can cut it with the best sides in Europe but then being caught cold against teams they are expected to beat - like Connacht.
Biarritz know their chances of reaching a ninth quarter-final in European rugby's premier tournament are probably over for this season but a win would mean they could still make an impact on this Pool.
• Connacht out half, Dan Parks, is now the leading points scorer this season in the Heineken Cup with 48 points.
• Biarritz have retained possession of the ball at 98% of the rucks and mauls they have contested this season, the best figure in the tournament.
• In Biarritz' last nine matches, they have followed a defeat with a victory. Should this run continue, they will turn Connacht over this weekend.
• Connacht have won three of their last four Heineken Cup matches, after losing their first five straight in their debut season last year.