Iga Swiatek has revealed she was "crying for 40 minutes" when she discovered Ash Barty had retired and the Polish sensation has felt "a range of emotions" after becoming world number one.
Barty sensationally called time on her career at the age of 25 last month.
The Australian quit while she was at the top of the rankings and on the back of winning her home grand slam for the first time at Melbourne Park in January.
Swiatek on Monday became Poland's first world number one and the 20-year-old could be hard to dislodge, as she is on a 17-match winning run.
The 2020 French Open champion became the youngest woman to win the Sunshine Double on Saturday when she beat Naomi Osaka in the Miami Open final after being crowned champion at Indian Wells.
Swiatek was in tears after finding out that Barty had ended her playing days and it soon sunk in that she would officially become the best player in the world.
She told BBC Sport: "I was crying for 40 minutes. Mainly, it was because of Ash's retirement. I didn't know it was going to happen and it really surprised me.
"I always had this vision that we would all play until we are 35 or something, until our bodies are so tired that we can't anymore.
"I needed time to actually understand what she must have thought. Her decision was really brave and I felt a lot of emotions because of that."
She added: "I also felt emotional because of my own position.
"I realised after two hours of being really emotional that 'hey, you don't know what is going to happen yet and you still have to win some matches'.
"So I told myself 'let's wait with the emotions and with being excited because I have work to do'."
Swiatek won the Qatar Open before claiming another two prestigious titles in the United States and the Warsaw native says the manner in which she has dominated has taken her by surprise.
"Emotionally it has been really intense and I have felt a range of emotions – from being proud and having satisfaction, to confusion and surprise," she said.
"These last weeks showed me I can trust in myself a little bit more and trust my skills and my tennis. Before I didn't really know it was possible for me to have a streak like that. So it also kind of surprised me.
"After Doha and after Indian Wells I didn't have time to digest what I've achieved. Right now I am going to take some time to analyse what happened from a 'work' point of view."