After winning 26 singles titles during her career, Ellerbrock went to the top of the world rankings in 2013.

She won two Grand Slams during her career – the French Open in 2013 and then the Australian Open in 2014. 

The German also appeared in five other Grand Slam finals, with her last final coming in a straight sets defeat to The Netherlands' Diede de Groot at Wimbledon in 2017.

She ends her career with the Tokyo 2020 Paralympics now postponed to next year because of the COVID-19 outbreak.

Ellerbrock spoke about some of the pressures of being the world number one.

She said: "One of my greatest goals had been achieved, but I felt more pressure.

"Everyone who's been in that situation knows that it's easier to climb the rankings than to defend the number one spot.

"From that moment on, I set my goals differently, I tried to stay away from the ranking and focused more on exploiting my potential."

The next year she tasted success early on when she defeated Japan's top star Yui Kamiji in three sets in the final of the 2014 Australian Open.

After suffering from post-traumatic stress disorder after a surgery, she dropped from the top of the rankings.

Due to her injuries, health concerns and mixed results, she has decided to call time on her career.

Ellerbrock continued: "Until November last year, I always had a strict plan for 2020.

"My goal was to finish my career in Tokyo but I lost the fun on the court at tournaments.

"I've kept many wonderful moments and great people in my heart from my career, but I also knew the most brutal face of high sports competition, with some situations that affected me.

"Of course, I miss the training sessions and people at my training sessions in Hannover, just as I miss the Tour, but I think this is the only decision I could make, even when it was a very, very tough one and one I'm still dealing with emotionally."

The German has not made a decision yet on whether she will turn to coaching, focusing at the moment on her hobby of acrylic painting. 

She added: "I can't live without sports, that's for sure, I've been playing table tennis with my prosthetic leg and went back to cycling in the streets.

"I enjoy doing this, but people who know me know that I do things fully or not at all, I'm curious to find out how great my potential is." 

Ellerbrock was an able-bodied tennis player before she picked up a foot infection after an operation in 2007. 

She first played wheelchair tennis competitively in 2009.