The 29-year-old Kerber, who won the Australian and U.S. Open titles in 2016, was resolute in defence against her aggressive opponent and advanced to a first individual final since Monterrey in April last year.
"I am playing unbelievable tennis again and feeling just great".
I tried once, but it felt wrong, so I'm trying to hear everything and see what's happening.
"I think the draw was really tough".
Now it's happened, and it's not so easy, actually, to really get used to it-to wake up every morning and tell myself, "Okay, you really are now the no. 1 player in the world". I played some of my best tennis this week and it wasn't enough. I'm always trying to coming back, and this is what I was also trying the last few weeks to working hard and pushing me until my limits.
After this win, Kerber is to set her sights on preparing for the Australian Open, where she is scheduled to play in the first round against her compatriot Anna-Lena Friedsam on January 16.
"And also, now I know what I can do".
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For Paul's fans, however, the next act has become a waiting game to see what this internet personality is planning next. There was an immediately backlash of public outrage, and though the video was quickly taken down, the damage was done.
It was the Australian who had won their last meeting, beating the German in straight sets in Zhuhai last October, and it was her who got off to the slightly brighter start, looking comfortable on serve to begin with as she twice came close to breaker Kerber.
Sharapova was given a wildcard in Stuttgart in March past year, even though her suspension didn't allow her to play her first-round match until the third day of the tournament - a decision Kerber labelled at the time as "a little bit strange".
The other semi-final will be an all-Australian affair between Ashleigh Barty and Daria Gavrilova.
Barty had two break points on each of Kerber's first two service games and couldn't convert.
For Barty, 21, it was a fine start to the year, although she was unable to add to her one WTA Tour crown - won in Malaysia in 2017.
She then broke Barty in the fifth game to go 3-2 up again, and the second set followed the pattern of the first to land Kerber her first title win since September 2016.
"She's such a brilliant chick".