Then one day, while she was sitting on her sofa watching TV, she decided it was time to retire, just like that.
The Dutch grande dame of wheelchair tennis ended her career in 2013 on a winning streak of 470 matches -- an achievement second only to Pakistani squash great Jahangir Khan's record mark of 555 straight victories set in the 1980s.
An emotion fueled moment the previous summer had acted as a catalyst for Vergeer's decision to step away from competition.
After winning a seventh Paralympic gold medal at London 2012, she broke down in tears, explaining to the media huddled around her, "There was so much pressure on me. Everybody just expects me to win gold, expects it to be easy."
A new life
After toiling and training for 20 years, she thought enough was enough.
"It was such a relief to win that medal," says the 33-year-old Vergeer as she reflects on her self-imposed sabbatical. "So I decided to take a break after the Paralympic Games and I enjoyed not having to deal with the pressure anymore.
"I was at home watching the Australian Open [in 2013] and I realized I didn't miss it. I didn't want to be in Australia. I enjoyed being home so much more. I was 32 and ready to start a new life."
The transition from professional tennis player to a mere mortal was not easy for the wonder woman from Woerden.
Vergeer dominated her field, winning seven Paralympic gold medals, 21 grand slam singles crowns and 169 singles titles overall, plus 159 in doubles competition.
"It's difficult to be retired and not to be an athlete anymore," Vergeer explains. "There are some days that I miss it.
"Winning matches, getting applause, hanging a gold medal around your neck, I guess that is some kind of addiction, something you want to feel constantly.
"I don't have that anymore. Now in everyday life, it's not every day that people come up to me and say I'm doing great work.
"I had to get used to the fact that it's not going to be there anymore.
"As an athlete your life is also so structured; the time you get up, the time you could eat, when you could go on holiday.
"Now everything is possible and sometimes I make the mistake of planning my day too full, even after two years!"
She may be retired from the professional game but Vergeer still has a jam-packed to-do list.
Top of that list is running the Esther Vergeer Foundation
, which encourages children and youngsters with a physical disabilities to participate in sport.
The foundation helps organize sports days in the Netherlands but is also intent on improving sporting opportunities for disabled children around the globe.
"I don't think a lot of kids with disabilities go out there and play sports," she says. "That needs to be pushed and promoted. That's what I really want to do."
Vergeer's own retirement did, however, lead her to the realization that Para-Sport is now much more prominent -- and that's another positive trend she wants to nurture.
"When I announced my retirement it surprised me," she explains. "It blew me away that I got so much attention from all over the world from China, to Iran, to America.
"It made me proud, it made me realize that Paralympic sport was grown and known all over the world. That was something I fought for all my life, all my career.
"When I started playing wheelchair tennis there was hardly any recognition or knowledge of Paralympic sports.
"In the last 20 years, I've seen the sport grow. I've seen it become more professional and integrated.
"There were still moments when I thought 'I'd really like to be on that TV program' but then some athlete without a disability became the first to call and sometimes that frustrated me.
"Then I realized, we need to see the growing process. I think Paralympic sport will get more attention, will become more integrated and will get more recognition from sponsors and companies in the future."
Her peerless win-record helped Vergeer blaze a trail to promote Paralympic sport, notably when she posed nude
for the cover of ESPN Magazine's "Body Issue" in 2010. "Sometimes, as a disabled athlete, you must think outside the box," she told CNN at the time.
"I realize that doing the shoot was 'an edgy' thing to do but I didn't do the photos just to raise awareness of disabled sport.
"The aim of the magazine is to show how different types of bodies can perform well in sport and I hope that my photos will get that message across."
Vergeer is now proactively, and passionately, promoting another message -- increasing the number of integrated tennis tournaments.
The Wheelchair Tennis Tour, which began in 1992, arguably already matches the demands of the WTA and ATP tennis tours, with 160 tournaments in 40 countries per season.
The jewels in the crown of its tour are also the four grand slams -- the Australian Open, Roland Garros, Wimbledon and the U.S. Open -- which are staged in tandem with the prestigious able-bodied events.
"The ultimate dream I have for wheelchair tennis is that it's going to be a very integrated sport," says Vergeer, who is the tournament director for Februrary's ABM AMRO wheelchair tennis tournament
in Rotterdam which is played alongside the elite men's event.
"Able-bodied tournaments are one of the best platforms we have to showcase what people with disabilities can do.
"To show we are just human beings with ambition and a love of competition."
Vergeer was introduced to wheelchair tennis after she was left paralyzed following surgery to remove a clutch of blood vessels around her spinal cord when she was just eight years old.
"The moment they told me I would never be able to walk again is not the moment I remember very much," says Vergeer, who is paralyzed from the waist down.
But her first competitive tennis match a few years later still very much lingers in the mind.
"I was so excited and nervous. It gave me goose bumps and adrenaline. I really enjoyed it.
Since announcing her retirement from professional sport in February 2013, it is basketball -- a sport she gave up when she decided to combine tennis with her university studies in management, economics and law -- which has provided her with a regular dose of sporting adrenaline.
"I have to admit that I'm playing basketball now," Vergeer smiles. "I'm really enjoying being in a team and playing in competitions."
But inside the confines of the Center Point sports complex in Almere, just outside Amsterdam, the former tennis ace was persuaded to pick up a tennis racquet for the first time in 18 months for CNN's Open Court.
The emotions and muscle memories stirred for Vergeer may have revealed more than a recently retired tennis pro might have wished.
"I haven't played tennis for a while now after my retirement and I noticed that coming back to the court makes me feel free somehow," she explains.
"I feel strong, I feel fast. I feel in control, I love that! Now I realize a year and a half not playing tennis is too long.
"I think I'm going to go out on court more often."
Could 'Vergeer the Invincible' consider making a comeback in time for the 2016 Paralympic Games in Rio?
The Dutch ace is keeping her counsel for now but perhaps we shouldn't bet against 470 straight victories and counting.