An interprovincial that is also top of the table - it does not come much bigger or better for Connacht Rugby.
With just five Guinness Pro 12 fixtures remaining, Connacht face Leinster in the Galway Sportsground on Saturday (5.15pm ) in front of a capacity 7300 crowd, live on both TG4 and Sky Sport, and with the world's top referee Nigel Owens in charge.
Understandably the Sportsground was sold out by early Wednesday morning, including an extra 1400 seats specially for this encounter as Connacht bid to continue their lead at the top of the Pro 12 and Leinster, just a point behind, look to overtake them.
It is a new scenario for Connacht at this stage of the season, but one which Connacht deserve, says coach Pat Lam.
"We have worked hard to be here, and it's important to understand how we got there. It's just fantastic for Connacht Rugby, for the whole province, and everyone is looking forward to it.
Both sides are expected to name as many internationals as possible, and Lam has all five available for selection, although Ultan Dillane has a "few niggles".
That famous five - Connacht's biggest representation on an Ireland team - have enjoyed staggered returns to training this week, with the exception of Robbie Henshaw, who is not due back at the Sportsground till today (Thursday ).
"Kieran Marmion and Finlay Bealham joined us on Monday, Nathan White and Ultan Dillane returned Tuesday. Ultan has a few niggles at the moment, so will have to be monitored during the week, and Robbie Henshaw will join us on Thursday," says Lam.
"They all are available, but probably the tricky one to manage is everything we have done is as a team, and they have been away for a while. So I have to manage where they are mentally, where they are physically, and obviously the whole squad.
"Ultimately we are not a team of individuals. We have always focused on what we do as a collective, so we will balance this one game and make a decision on that."
Lam said Henshaw, having played every Six Nations game, needed extra recovery time, but he had been updated on this week's work. Nor was he worried Henshaw would be affected when facing his new Leinster teammates in opposition for the first time since deciding to leave his home province.
"He is so keen to finish well. I spoke to him after the test match, and you have to remember he played every minute of those games, and he's pretty battered and bruised, and on the weekend he took quite a big knock. But through all my time here, he's always been professional, we have a good relationship. I have sent him the stuff and he'll pick it up real fast, and I know he'll do well for us going forward."
Lam expects all five internationals, if selected, to make a valuable contribution.
"International rugby is great, it's at another level and you have good friendships, but when you come back and get onto the field it's all guns blazing at each other and doing the best for your team. They have done well and it's been huge having so many represent Ireland, but the pleasing thing is they have said that it's great to be back and are looking forward to contributing, not just this week, but for the run-in of our next six quality games."
Also back in training this week were hooker Shane Delahunt, scrumhalf John Cooney, and lock Andrew Browne, but absent is Craig Ronaldson who injured ankle ligaments in Connacht's win over Edinburgh two weeks ago. That leaves the position available for Henshaw to join regular centre Bundee Aki, while young Peter Robb and Api Pewhairangi could be on standby. In form wing Matt Healy is expected to start with either Niyi Adeolokun or Danie Poolman, while Aj MacGinty has a big role to play on Saturday, alongside Kieran Marmion. Up front Quinn Roux and Aly Muldowney started against Edinburgh, while in the back row John Muldoon is likely to return from No 8 to the blindside for Eoin McKeon.
Lam is looking for Connacht to convert opportunities into points.
"The biggest development for us is understanding the opportunities we create. When you consider we are playing a team of 31 internationals - we have eight - and they have the most caps in the Pro 12 with 8756 - we have the lowest with 50. But I don't see us as underdogs, but a high performing team. It's not about individuals or internationals coming back, what I am trying to stress is the importance of the collective."
"I think another testament is that we have Nigel Owens, the No 1 referee in the world, but they have earned it. Now there is responsibility to the game itself, and everything else is peripheral. It was a good week last week in Westport, and now this week everyone is fighting hard to get the jersey and there is some serious competition here. I am buzzing about Connacht Rugby at the moment."