The fifth seed suffered a 6-1 6-2 defeat to the 24-year-old, who became the first Slovakian to reach a Grand Slam final.
"I felt like I was in slow motion," BBC Sport quotes Radwanska as saying.
"I had a couple of tough matches and I think I was not fresh enough. She played well in the whole tournament, but I think I spent twice as many hours as her on court."
Cibulkova will take on Li Na in the final in Melbourne.