A home defeat to Northampton Saints last time out however has ensured that Leinster's progression to the knock-out stages is not assured, even if they currently top of their pool.
This weekend they travel to French champions Castres and they could find themselves knocked off top spot should they return empty-handed.
And the importance of the trip has not been lost on New Zealander Gopperth.
"This will define our season," Gopperth told the Irish Independent.
"We want to be in the last eight of the Heineken Cup.
"Castres are unbeaten at home throughout every competition, so it's a pretty big fortress for them. We have to make sure that we are on top of our game to go down there and get a result.
"Everyone knows they are a pretty physical bunch. They have got a massive pack, but their backs also love to offload. They love creating opportunities and if you kick poor against them, or if your kick-chase is poor, they will make you pay.
"We have got to make sure our basics are done well and we put pressure on them a lot in the right areas of the field."
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