It was a repeat of the gold medal match at the Tokyo Paralympic Games earlier this month, defeating second seed Yui Kamijee of Dutch top seed Japan 6-3 6-2 in the women’s match at the Louis Armstrong Stadium.
“For a long time it was not possible because there was not a single event at Wimbledon. Now for a few years they have had it … it is great to see the tour and the professionalism grow every year,” de Groot told reporters.
“It’s so special to actually be the first person to get that title. I don’t think I’ll ever forget it.”
Shortly later on Sunday, Australian top seed Dylan Alcott also completed a Golden Slam in his respective event after beating Dutchman Niels Wink 7-5, 6-2 in the wheelchair quad singles final.
Alcott is the first male wheelchair tennis player to complete the Golden Slam.
Djokovic wanted to win a record 21st Grand Slam title and the first men’s calendar Grand Slam since Rod Laver in 1969 – winning the Australian Open, French Open, Wimbledon and US Open in the same year.
Djokovic missed out on his chance to win a gold medal when he was knocked out in the Olympic semi-finals by eventual gold medalist Alexander Zverev before losing the bronze medal match to Pablo Carreo Busta.