The Pole, seeded fourth for Melbourne Park and a winner in Auckland last week, secured her ninth straight victory from the start of the year in a little over an hour of one-sided tennis when the hapless Cibulkova double faulted.
Radwanska tempered her celebrations out of respect for her opponent and said she felt sympathy for the Slovakian, who had beaten three top-10 players on her way to the final.
"That's tennis and these things happen," she said. "But I feel bad...because for sure she didn't deserve that result.
"It's been an amazing two weeks," Radwanska added. "I've won two titles and not lost a set. If I can play like that in Melbourne, I'll be very happy."
In the Hobart warm-up, Russian Elena Vesnina upset American eighth seed Sloane Stephens 6-2 6-2 to reach Saturday's final, where she will play defending champion Mona Barthel, who beat Kirsten Flipkens 6-4 6-4 in the later semi-final.
WTA Sydney result
1-Agnieszka Radwanska (Poland) beat Dominika Cibulkova (Slovakia) 6-0 6-0
WTA Hobart results
9-Mona Barthel (Germany) beat Kirsten Flipkens (Belgium) 6-4 6-4
Elena Vesnina (Russia) beat 8-Sloane Stephens (U.S.) 6-2 6-2