When Caroline Wozniacki waved farewell to the professional tennis circuit in January 2020, the retiring former world number one genuinely thought that was it.

The fire reignited shortly after the 33-year-old gave birth to her second child last October, leading to the announcement in June she would return to the WTA Tour.

After playing in Montreal and Cincinnati, she springs back to Grand Slam action at the US Open on Monday.

"I didn't play for a very long time. I didn't miss it," said Wozniacki, who won the 2018 Australian Open title and spent 71 weeks as the world's leading player.

"I played since I was very, very young. It's been part of my life and my lifestyle for so long. I needed a break."

The Dane had been diagnosed with rheumatoid arthritis 18 months before she quit, but had also made it clear she wanted to "achieve other things in life".

Wozniacki had enrolled at Harvard Business School and planned to explore the world in what she described as a "slam-packed" diary.

A belated honeymoon with her husband David, the former NBA basketball star she married in 2019, took in Australia and New Zealand before the pair climbed Mount Kilimanjaro and also hiked through the Polish mountains.

Then, a year after Wozniacki retired, she announced she was pregnant with her first child and gave birth to daughter Olivia in June 2021.

The family was extended further with the arrival of a son, James, last October.

Shortly after his birth, she found the racquets.

"I started just missing the cardio aspect. I'll always love the game, no matter if I'm 33 or if I'm going to be 80," said Wozniacki, ahead of playing Russian qualifier Tatiana Prozorova in the evening session on Louis Armstrong Stadium.

"I hope I'm always going to be fit enough that if I want to go out there and hit some balls, play some doubles or whatever, that would be a possibility with my friends.

"It just happened to be that I felt like I was hitting the ball extremely well, that I still am young enough to give it another shot.

"You only live once, so why not?

"When you look at yourself and you feel like you still have a chance to do something really cool and really good, then you have got to take the chance.

"You never know if you don't try it."

One of the defining features of Wozniacki's career has been her competitiveness and unwavering desire to prove people wrong.

Consider that journey, step by step.

Now Wozniacki, who is confident her body will hold up, is looking to defy the odds again and pose a challenge to the younger generation now leading the WTA Tour.

This is not intended to be a one-off return, with Wozniacki planning to play a fuller schedule in 2024.

Inspiration can also be drawn by seeing several of her peers - including close friend Serena Williams - having returned to the top after having children.

"I'm proud that there are quite a few mums on tour that have paved the way for the future generation.," said Wozniacki.

"It's possible to take a break, have a family, then come back. The women have showed that you can still play at a very, very high level.

"I realise that I'm not that young any more. But you have older players.

"I'm enjoying being here in the moment. I didn't think three years ago that I was going to be here, so this is awesome."