Saracens' Mako Vunipola ready for tough battle against Northampton in Aviva Premiership semi-final There's always an edge when we play them. Northampton are one of our closest rivals so it makes it even better. It's knockout rugby, a semi-final, there will be a bit of tension but that's always part of the game. Vunipola again forged an effective front row partnership with Matt Stevens, another surprise Lions pick, who helped turnover Bath at an important five metres scrum in the second half before he was replaced. "Matt has played some of his best rugby and he's enjoying playing for Sarries and for him to get [Lions] recognition is fabulous and deserved," Vunipola said. There will be no trophy for Saracens topping the table at the end of a gruelling eight months of rugby in which they were the only club to boast an unbeaten home league record which included matches at Twickenham, Milton Keynes, Wembley, Watford and their new permanent home in Barnet. "It gives us a massive confidence boost to know that we finished top of the table but it's knockout rugby and anything can happen really and we are fully aware that Northampton will be coming here looking to turn us over," Vunipola said. To have a perfect home record is great thing for us as a team but we all know that next week is going to be a tough game. Saracens will face Northampton without No 8 Ernst Joubert, who damaged medial knee ligaments in the Heineken Cup semi-final defeat by Toulon. But flanker Will Fraser (shoulder) and England centre Brad Barritt (ankle) could be back in contention. Bath's defeat meant that they missed out on Heineken Cup rugby next season although a win would still not have been enough to secure the sixth qualification place as Exeter beat Gloucester. "Over the course of the season we have dropped too many points against sides below us in the table," admitted Bath defence coach Mike Ford. Bath remain in talks with Gavin Henson but the former Wales utility backs has not yet signed a contract for next season. "Henson has not been signed so we are still looking and discussing who to get there," Ford said.