The Scarlets, edged out of the Pool leadership by Northampton Saints on try count, beat The Borders away 41-10 in Round 2 but Buchanan insists "there are no easy games in the Heineken Cup and this has become an extremely important game for us.
"We were delighted with the bonus point at Agen, although we could have come away with all four, despite the atrocious weather turning the second half into something of a lottery.
"Now we have to keep the momentum going against The Borders and after the weekend we will know exactly where we stand for our trip to Northampton - and what we have to do.
"However, if we win our last two games we qualify. It is all down to ourselves and you cannot ask for more than that in the Heineken Cup."