Kerber won her four matches at last week's mixed teams Hopman Cup in Perth before her five victories in Sydney.
Kerber will play Camila Giorgi in the semifinals.
The German player defeated Ashleigh Barty in straight sets, 6-4 6-4, after an hour and 11 minutes in the Sydney final to win her 11th career title, the first one since 2016 US Open.
Nevertheless, her appearance in the tournament decider will lift the 21-year-old Queenslander's world ranking to No.17 as she embarks on a home slam campaign flush with expectation.
Kerber eased to a 6-2 6-3 triumph, reaching the Sydney final for the second time in her career having lost to Tsvetana Pironkova in 2014, and her first in any tournament since April a year ago.
"I am playing wonderful tennis again and I am just feeling great".
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A double-fault midway through the first set cost Barty a crucial break point as Kerber claimed the first set 6-4.
"To be honest, I felt like I probably played some of the better tennis that I have this week".
Barty was in further trouble when she immediately surrendered serve in the second set, but in the second game she broke back to level at 1-1, igniting the home crowd.
Barty pushed hard early and had multiple break points on each of Kerber's two opening service games.
Barty was looking to become the first Australian woman to win in Sydney since Alicia Molik in 2005.
Barty said she would be ready for her Australian Open first round opponent Aryna Sabalenka of Belarus.