The Bees will make the short trip to their more illustrious west London neighbours this weekend for a fourth round replay that will live long in the memory.
Around 6,000 Brentford fans are expected to make the trip to Stamford Bridge, just three weeks after holding the European champions to a 2-2 draw at Griffin Park.
Only Fernando Torres' equaliser seven minutes from time saved Chelsea from one of the great FA Cup shocks, but Rosler believes an upset is still on the cards.
"I think first of all there will be a big factor of excitement going to Stamford Bridge," the former Manchester City forward said.
"I think excitement will take over and they will be very motivated. My players will raise their standards in terms of physical capabilities, hopefully by five to 10 per cent, which is needed to compete.
"Obviously Chelsea will take us more seriously than the first game and I am looking forward to what will be a great test for us, for everybody involved.
"I still believe it is possible. The chances are slimmer but I think it is still possible.
"The crucial thing for us is that we are competitive in the first half an hour.
"We need to keep it at 0-0 in the first half an hour, keep our options open and also be brave to attack them."
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