After a tight 70-minute opening set in which both players dropped serve twice, Li took two-thirds of the points in the second set to win the Australian Open women's title for the first time.
A first-game break allowed Li to build a 3-1 lead in the opening set but Cibulkova, seeded 20th, evened the set at 3-3. Li moved ahead to 6-5 with her second break but Cibulkova answered to force the tiebreaker.
It was here Li took over, winning five of the first six points in the tiebreaker before finishing off the set.
Li won three straight points to take the first game of the second set on serve and then four straight to break Cibulkova's serve for a 2-0 lead. A backhand winner gave Li a two-break lead later in the set and she capped the tournament with her fifth break of the day.
It is Li's second major tournament title overall, adding the Australian Open to her 2011 win at the French Open.
It seemed Li, seeded fourth in Melbourne, was fated to win the tournament. She narrowly survived a third-round challenge when a match point for Lucie Safarova landed 2 inches out. A series of upsets across the draw meant Li didn't have to face any player ranked in the Top 20 (Cibulkova is No. 21 in the rankings).
But she beat everybody who showed up. She dropped just one set in the tournament -- the first set against Safarova. Her previous finals at Melbourne had been close. She lost to Kim Clijsters in 2011 final in three sets and to world No. 2 Victoria Azarenka in three sets last year.
Cibulkova had been to one Grand Slam semifinal -- 2009 at the French Open -- before this year. Unlike Li who didn't see higher-ranked players, Cibulkova needed a series of upset wins to get to her first major tournament final. She beat 16th-seeded Carla Suarez Navarra in the third round, took out world No. 3 Maria Sharapova in the fourth, defeated No. 11 Simona Halep in the quarterfinals and then fifth-seeded Agnieszka Radwanska in the semifinals.