The world number nine was in control throughout in an all-German clash at the WTA International clay-court event, cruising through 6-2 7-6 (7-0).
And the 26-year-old was pleased to get another victory under her belt ahead of the French Open in four days' time.
"The first set was good - I was feeling good and I found my rhythm," Kerber said.
"In the second set Anna-Lena was playing great. She was playing much more aggressive. But I was happy about my game plan and that I was able to win, and I'm really happy to get more matches before Paris."
However, there was a shock in the other all-German affair of the day as Mona Barthel knocked out eighth seed Annika Beck 6-2 6-4.
Barthel needed just an hour and nine minutes to dispatch a player ranked 30 places above her, breaking Beck five times in a dominant performance.
The 23-year-old Barthel will now face Ukraine's Elina Svitolina in the last eight after the fourth seed took care of Spaniard Beatriz Garcia Vidagany 7-6 (7-5) 6-3.
But there was disappointment for another home hope Dinah Pfizenmaier, who suffered a three-set defeat to Caroline Garcia of France 7-5 5-7 6-3.
Pfizenmaier showed resolve to send the contest, which lasted two hours and 25 minutes, to a decider. However, the seventh seed's quality shone through as Garcia booked her place in the quarter-finals.