Demi was born in Sittard on August 1, 1993. She was raised in Nieuwstadt; with only three years old, she had her first training with a half squash racket. In the following years Demi was playing tennis in TC Born. At eight years, she started to train in LTA with Tom Devries. At this moment, Demi is still training at LTA in Maaseik. Demi was an active kid and combined tennis and football from her six to 12 years. With the higher risk for injuries in football, she decided to stop and moved her focus for 100% to tennis.
From her 17th on, Demi started to play professionally. Nice to know is that she spends more time with the Belgians then with the Dutchies. This also explains her Belgian accents when you have a conversation with her. In 2011 she reached one of her career highlights as she qualified for all 4 Grand Slams junior finals in doubles, and she wins Australian Open and US Open. What was even more special is that she did this with four different doubles partners.
When on her 18th she had to move up from juniors to seniors, she had to start from the beginning again down from the bottom but her hard work paid off. As in 2012, she got selected for the Netherlands FedCup, ‘’for my feeling that’s where my tennis career started’’. In 2015 she chose to put her focus 100% on doubles, which turned out as a right choice because later that year, she wins her first WTA in Katowice and the second one in WTA Boekarest. From then on, she competed in the main draw from the Grand Slam events. At this moment, she is ranked 12th in the world doubles ranking (October 19, 2020).