Sabalenka, who won the Qatar Open in 2020, suffered a second-round defeat to Ekaterina Alexandrova in Doha last week.
Three times Grand Slam champion Sabalenka started her season with a title in Brisbane but has struggled for form after failing to win a third consecutive Australian Open last month.
"I'd say that for the last couple of years, I'm not doing well in the Middle East. I believe we need to change something in the preparation... because every time I don't feel well playing here," the 26-year-old Belarusian said after Wednesday's match.
"Even health-wise I'm struggling. Australia always taking a lot of energy out of me... I believe that I'm not that hungry on court. I'm kind of like all over the place in my thoughts and not consistent. The decisions I'm making on the court are a bit wrong and emotionally I'm not at my best."
The 22-year-old Dane broke Sabalenka's serve six times to secure her first WTA 1000 quarter-final spot. Her victory also served as payback for her third-round loss to Sabalenka at Melbourne Park.
"Last time, I had my chances, but I didn't take them," Tauson said.
"Today I was really free in my mind. I knew she had to beat me and I'm the underdog all the way, and I was really enjoying my time out on the court."