Sabalenka saved a match point and came roaring back from 5-2 down in the third set to win a thrilling last-16 contest 2-6 6-4 7-6 (7-5) at Eastbourne.
Next up for the Belarusian is a meeting with Kiki Bertens, who she has not beaten in three previous meetings. Bertens was a 6-3 6-3 winner over Anna-Lena Friedsam.
"Something unbelievable happened today and I'm so happy that I won this match," said an ecstatic Sabalenka in an on-court interview. "It's a really important win for me."
In the week before Wimbledon, 2017 French Open winner Jelena Ostapenko retired from her match with Ekaterina Alexandrova due to a left hip injury, while trailing 6-3 2-1.
Alexandrova now faces the daunting challenge of toppling second seed Karolina Pliskova, who demolished Elise Mertens 6-1 6-2.
The pick of the quarter-final ties will be a meeting between two former world number ones in Simona Halep and Angelique Kerber. The Romanian came through a three-setter with Polona Hercog while Kerber beat Rebecca Peterson 7-6 (7-4) 6-0.
Home hope Johanna Konta suffered a surprising 6-3 6-2 loss at the hands of Ons Jabeur, who will take on Alize Cornet - a straight-sets winner over Zhang Shuai - in the last eight.