The 31-year-old Ukrainian swept aside French Open champion Coco Gauff 6-1, 6-2 in the quarter-finals on Tuesday, ending the American third seed's bid for a third Grand Slam title.
Svitolina, the 12th seed, reached the last four at Melbourne Park for the first time after three quarter-final appearances, keeping alive her hopes of a maiden major title.
"It was difficult decision in one hand, but then I spoke with my team and family," Svitolina told reporters. "If I would keep pushing last year, I think I would not start here. I would be exhausted, and even not sure if I would be injury-free.
"So for me it was important to just step back, and I'm very happy that I did that. Of course, now it's easy to say because the results have been great... but I still think it's something that helped me."
Svitolina won the Auckland Open this month, her 19th WTA title, after ending her 2025 season early to focus on her mental health.
Asked whether she surprised herself with how quickly she rediscovered her form, Svitolina said: "I tried to trust myself... When I'm fresh, when I'm mentally ready to face difficult situations, then I can play well."
Svitolina next faces Belarusian top seed Aryna Sabalenka, against whom she holds a 1-5 losing record.
"It's no secret she's a very powerful player," Svitolina said. "The power in all parts of her game is her strength. I think she's very consistent for the past years with everything that she does on the court. I'll have to be ready for that, try to find the ways and the little holes, little opportunities in her game."