She held down eighth place after the first runs but dropped back to 10th in the second and final round.
"I was quick over the flat part of the course but the biggest part of this sport is nailing precise race lines while paddling at full speed and unfortunately I didn't do that as well as I would have liked."
While the river on which the World Cup events were contested was good and the course technical enough to keep everybody on their toes, Cairns said it was apparent that further upstream the locals used the river as a dumping ground as plastic bottles were constantly seen floating along it.
The quality of the water created other hassles as she was one of several athletes to suffer "Krally Belly" (nick-named after the main township of Kralijevo).
Cairns had been hoping a canoe club in Germany would have a boat for her to train in during the final stages over her build-up for Serbia but that didn't happen and she was forced to do all of her sessions on a rowing erg at a gymnasium.
"This definitely kept my fitness up but when it comes to the rough stuff nothing beats time on the water and it was just unfortunate I probably didn't have enough of that."