After a 10-year winning streak in wheelchair tennis, Esther Vergeer felt she had nothing left to prove.
The 31-year-old Dutchwoman retired Tuesday, ending one of the most amazing careers in any sport.
"I'm hugely proud of my performances, my titles, and can look back on my career with a great feeling," Vergeer said at the ABN AMRO tournament in Rotterdam. "Keeping going would not add anything."
Vergeer won the women's singles gold at four straight Paralympics starting in Sydney in 2000 and ending in London last year. She also won 21 Grand Slam singles titles, 23 Grand Slam doubles titles, three Paralympic doubles gold medals and a silver. Overall, she won 148 singles titles and 136 in doubles.
Vergeer took a break from the sport last year to consider the future after her Paralympic gold medal took her remarkable winning streak to 470 matches. In all those matches, she only faced one match point, in the final of the 2008 Beijing Paralympics.
Vergeer's retirement means she will not surpass what is widely believed to be the longest run of consecutive wins in sport — 555 by Pakistani squash great Jahangir Khan from 1981-86.
Like Khan, she was in a class of her own.
In the last 10 years, she won 120 straight tournaments, beating 73 different opponents, winning 95 matches 6-0, 6-0 and dropping only 18 sets, the International Tennis Federation said.
Sitting on the couch at home in the snowy Netherlands last month and watching the Australian Open on television, she knew it was time to end her playing career and concentrate on her efforts to promote sport for people with disabilities through a foundation she set up.
"It felt great," she said, choking back tears.
In a measure of Vergeer's status in Dutch sport, soccer great Johan Cruyff attended her announcement and wrote a foreword in the book about her life and career that she also presented to the media.
Sportspeople like Vergeer, "should be an example to us all," Cruyff said.
Roger Federer paid tribute in another foreword in the book.
"She is an astonishing athlete, a huge personality and she has achieved one of the most amazing feats in our sport," Federer wrote.
Vergeer, who was 8 when she lost the use of her legs following surgery to repair blood vessels around her spine, started playing wheelchair basketball while she recovered. She was good enough to make the Netherlands national team before focusing on tennis.
She rose to No. 1 in the wheelchair rankings in 1999 and never relinquished the top spot.
"Esther Vergeer is a tremendous ambassador not only for tennis but also for disability sports. She is an inspiration to many," ITF President Francesco Ricci Bitti said. "Wheelchair tennis owes her a huge debt of gratitude for her professionalism and her quality as a player."
The last time she lost a match was to Daniele di Toro in Sydney on Jan. 30, 2003.
"To be honest, I don't really know or remember what it feels like losing in singles," Vergeer said. "I've lost a couple of times in doubles, so I know what it's like to lose.
"And I know what it's like to lose a Monopoly game and I don't like losing. But this doesn't feel like something I lose. This is not the same thing at all."