Ahead of the Heineken Cup quarter-finals, we look at the key men who could be the difference between winning and losing.
Munster v Toulouse, 1pm, Sat, Sky Sports 2 HD
Munster - Peter O'Mahony
It will be a massive blow for Munster if their inspirational captain does not recover from his persistent hamstring injury. Perhaps he is not the biggest of back rowers but O'Mahoney more than makes up for it with his attritional style of play - especially at the breakdown where he is very hard to clear out. In a team with the likes of Paul O'Connell, Donnacha Ryan and Donncha O'Callaghan, O'Mahoney epitomises everything about Munster and many Munstsr fans will want to see him start against Toulouse, even if it is on one leg.
Toulouse - Louis Picamoles
Another player who is in doubt for quarter-final action and Toulouse will be hoping their big No.8 overcomes his hip injury. With 27 defenders beaten this season, Picamoles is one of the best No.8's in world rugby today and a crucial player for Toulouse. He will be disappointed with his performance in the Six Nations - where he was dropped after showing disrespect towards a referee, but will give Toulouse that vital front foot ball and will carry all day long.
Clermont Auvergne v Leicester, 4pm,Sat, Sky Sports 2 HD
Clermont Auvergne - Sitiveni Sivivatu
Sivivatu tops the table in this year's competition as far as clean breaks go with an impressive 14 and will be looking to improve on that number come Saturday. Sivivatu has an incredible turn of pace and some superb footwork for such a big man - he can run through you or around you. Tigers beware!
Leicester - Ben Youngs
Leicester's pack will go toe-to-toe with anyone all day long but it is outwide where they have added an extra dimension to their play. The likes of Manu Tuilagi, Vereniki Goneva and Miles Benjamin have certainly given them plenty of attacking options outwide. It will be up to Ben Youngs to supply them with the ball that is needed and to make the right decisions. With Richard Cockerill putting his trust in the inexperienced fly-half Owen Williams, Youngs stamp on this game will be even more important.
Ulster v Saracens, 6pm, Sat, Sky Sports 2 HD
Ulster- Ruan Pienaar
There is no doubting the quality in the Ulster squad but it is Ruan Pienaar that everything seems to revolve around. His performances for the Irish province have made the Springbok a firm favourite at Ravenhill. Pienaar is far from the fiery hot-headed No.9's we are used to seeing like Mike Phillips and Conor Murray however he is just as deadly; able to glide through a gap and kick for posts or territory with pin-point accuracy. He has so much time on the ball and his decision making gives everyone around him confidence. If he fails to recover from his shoulder injury it will be a huge blow for Ulster.
Saracens - Owen Farrell
The Six Nations saw Farrell come on in leaps and bounds with his attacking and running game and he will be looking to unleash that for Saracens on Saturday. Farrell's boots is always reliable and his tackling pretty formidable but it is his decision making which could prove crucial for Saracens success.
Toulon v Leinster, 4.30pm, Sun, Sky Sports 3 HD
Toulon - Jonny Wilkinson
What can you say about this legend of the game? While Matt Giteau will no doubt cause havoc in the mid-field with his running game, it is Wilkinson who will take control of his forwards and ultimately decide how they play. We are expecting Toulon to use their powerful forwards to great effect with Wilkinson kicking for territory and making Leinster pay for any indiscretions.
Leinster - Cian Healy
Leinster will have to have all their big names on the field and firing on all cylinders if they are to upset this Toulon side who will play the power game all over the paddock. It is crucial that Leinster get a solid platform and Cian Healy will play a huge part in that area. The loosehead missed last week's Rabo Direct game against Munster but Matt O'Connor will be moving heaven and earth to get him back. Healy will need to bring all the tools of his trade with him on Sunday when he comes up against Carl Hayman - including his ball carrying expertise to help get Leinster on the front foot.