Mullin and Dampney finished in third place in Pool F, but will now play two matches as lucky losers hoping to qualify for the elimination phase after losing 2-0 – 25-23 21-13 - to Russian pair Evgeniya Ukolova and Ekaterina Khomyakova.
And Mullin believes she and Dampney must make the most of the opportunities presented to them if they are to progress.
“I am really disappointed obviously,” she said. “We had three set points in the first set, but we could not close it.
“We had our opportunities in the first set to close it out and we were a bit aggressive with our serving – I think we should have made them play a bit more.
“We actually work quite hard on being in a bubble on the court. We need that to focus and to be able to communicate.
“We’ve never experienced this much support before and it’s unbelievable, and of course we hear them in between points.
“Now we have to go back and there’s lots of hard work to do before that match.”
Dampney believes the pair need to regroup and focus on what they are good at if they are to qualify – but admitted she was slightly disappointed with the referee.
She said: “It’s all or nothing. We’ll relax, eat, chill, stretch, talk to our coaches – we have to regroup and then we’ll be ready to go out there fighting.
“I thought the referee was very strict, but obviously you have to deal with that in beach volleyball.”