Leinster resume the defence of their Heineken Cup crown with a Round 3 trip to Parc y Scarlets on Saturday with coach Michael Cheika warning "this is the real business."
Just six days after Newport Gwent Dragons knocked Leinster off the top of the Magners League with a try bonus 30-14 victory, the European champions return to Wales to take on the Pool 6 leaders in the first of their critical back-to-back showdowns.
"December and January are when you really make your pitch for the rest of the season - and for us that starts on 12 December," said Cheika.
"The Scarlets are the leaders of the group and that puts them in a commanding position while having the home leg of the back-to-back games against us first is a massive benefit to them.
"We are at the stage of the tournament where you stare at the opposition and make sure you don't blink first - this group looks as if it will be going down to the wire.
"All the Pool 6 matches are massive for all four of us and, as far as I am concerned, the only thing that matters is that on Saturday we perform at a level to get the win at the Scarlets.
"Obviously the Scarlets are a highly efficient attacking outfit, with a very good axis at 8, 9 and 10, and lots of pace out wide and not scared to have a go - they are a high scoring attacking team and we will do some homework on them.
"We are in a situation where we are missing a few guys but also pretty happy with the way we have developed."
Leinster were not alone as both teams had disappointing domestic weekends with the Scarlets losing 16-17 to Edinburgh in west Wales. But in the Heineken Cup the Scarlets are the ones who are two from two and Leinster one from two and Cheika admits "we had a Round 1 loss against London Irish and that has put a bit of an edge on things.
"Of course we were unhappy with our defence against the Dragons but we had rested a lot of players and I don't think you will see that many of them in the match-day 23 on Saturday.
"However, after this disappointing defeat we are obviously very eager to go and take on the Scarlets on Saturday and we will look at that as another game and, as after any loss, all you can do is get ready for the next challenge."