Only once before since the introduction of regional rugby in 2003 have Wales enjoyed an opening day clean sweep when in the 2006 / 2007 tournament the Blues beat Bourgoin, the Ospreys overcame Sale Sharks and the Scarlets accounted for London Irish.
And, in a mirror image of this season, Newport Gwent Dragons were then contesting the Amlin Challenge Cup competition.
The Saints are 3-2 ahead in tournament meetings with the Scarlets, including a 31-28 semi-final win at the Madejski Stadium that ended the Scarlets hopes before the Saints went on to lift the Heineken Cup by beating Munster 9-8 in the 2000 Twickenham final.
Wales centre Jonathan Davies - a try scorer against Castres - is relishing the contest against the Saints and the chance of meeting up with former Scarlets scrum half Martin Roberts.
"Northampton is a great place to go," he said. "I have played there once before and they have such great support.
"They are a very physical and strong team but we have got a lot of confidence from our performance against Castres and we have to make sure we can match up with one of the best teams in Europe.
"And we know all about the quality Northampton have throughout the team and on the bench from them reaching the final last year.
"They were very unlucky not to win it and I'm sure a massive motivation for them is going one better this time.
"They have a powerful pack, some big ball carriers and pace out wide so they are a threat all over the park.
"However, we are confident that, if we can get a fair share of the ball, we have players to do something with it.
"We enjoy playing together and once we get confidence and forward momentum, we have got ability on the ball and some good ball players that can create a good game - so it's really exciting.
"Our forwards fronted up massively against Castres, who were very physical, stopped them in the first half and took the game away from them.
"That enabled us to capitalise with a high tempo and Castres tired in the end and we were able to push forward.
"I think it was key to get that score line and to take the losing bonus point away from Castres as that could prove very important later on as at the end of the group stages one point can be the difference so it was a real confidence booster.
"The brand of rugby we play here is a very exciting one. Sometimes it's high risk and we can run ourselves ragged a bit but when it comes off it's great to be a part of."