And it's make or break for some of our top sides.
Cardiff may have made it to the Celtic League semi-finals, but they have lost both Heineken Cup matches so far this season, and now have a must-win game against Northampton.
Neath will take on Cardiff in the Celtic League semi-final, but first they have to deal with Italian side Amatori & Calvisano. A big victory for the All Blacks will give them a real chance of progressing to the knockout stages.
Last season's cup semi-finalists Llanelli have a tough away assignment to last season's PARKER PEN SHIELD winners Sale Sharks.
Newport, having lost their first two games in the competition, are playing for pride, and a game against London Irish will test just how much progress the Gwent club are making.
And Swansea will be looking to chalk up their first Heineken Cup win in two years but their opponents Bristol Shoguns still have quarter-final aspirations and will prove a tough match for the St Helens side.
Heineken Cup preview- Pool By Pool
Pool leaders Beziers have a real chance of putting one foot into the Cup quarter-finals when they host defending champions Leicester. The Tigers are struggling at Zurich Premiership level and the loss of key backrowers Neil Back and Lewis Moody gives the French side a royal chance of an upset on home soil.
In the other match, Amatori & Calvisano host Neath, who go into the match as raging hot favourites. The All Blacks need a big win to get back into contention for the quarter-finals and will be confident after their gritty Celtic League victory over Pontypridd on Friday night.
Viadana have the daunting task of travelling to Musgrave Park and facing a Musnter team desperate for a try-laden victory to make up for their first-round loss to Gloucester. With virtually an entire international XV at his disposal, including goal-kicking whiz Ronan O'Gara, Munster's Australian coach Alan Gaffney will be looking for a mistake-free performance.
Cup favourites Gloucester host Perpignan and another victory will see the bookmakers bring their odds even further in.
In arguably the tightest pool, last season's Cup semi-finalists Llanelli travel to Sale Sharks to try to make up for their scrappy loss away to Bourgoin in Round 2. With key player Scott Quinnell retiring from international rugby to concentrate of the European competitions, and Wales international fly-half Stephen Jones in terrific form, the Scarlets go into the match as slight favourites.
Bourgoin host Glasgow and will be looking to cement their spot at the top of the pool. The Scottish side will still be angry about letting the Celtic League quarter-final slip to Ulster on Saturday.
Montferrand take on Leinster in one of the matches of the round, and the Irish visitors will be eyeing the home side's injury list with relish. Underestimating a French side on their own ground is a dangerous option, however, and Leinster will need their big guns in top form to return with the points.
Swansea are at home to Bristol Shoguns and are desperate to turn their woeful season around. The Whites are effectively out of quarter-final contention, but still pose a threat in this Pool.
Edinburgh are still reeling from Cardiff's incredible comeback victory in the Celtic League quarter-final at Meadowbank on Saturday, and now must take on the might of French giants Toulouse. Captain Todd Blackadder will have to call on all his international experience to rally his troops for this one.
Newport are finally starting to show some form this season, and pose a tricky obstacle for London Irish. On form, the English visitors should sneak this one, but it could just as easily mark the start of the Newport resurgence.
Ulster host Biarritz Olympique in a match too close to call. Biarritz have proven they can win on the road by beating Cardiff at the Arms Park, but Ulster are confident after making the Celtic League semi-finals and ace goal-kicker David Humphreys will be doing his best to keep the French at bay.
Northampton are coming off a Zurich Premiership victory over Cup holders Leicester, but come up against a Cardiff side still grinning after their best performance of the season against Edinburgh. Too close to call, with perhaps home advantage proving the difference.