De Groot and Van Koot clashed in the first round of the singles event, and De Groot won that match before advancing to the finals, where she will face Yui Kamiji.
But now on the same side of the net, they managed to continue their formidable partnership, winning a total of seventh doubles trophy.
“I think what really helps is that we’re from the same country and we can train together,” De Groot said, after she and Van Koot rejected the British-South African combination of Lucy Shuker and Kgothatso Montjane.
“We started playing with each other for games, really to practice, to see if we could be a good pair in pairs. I think we just built and built from that.
“We are now at a level where we can win Grand Slams together.”
After a break in the first game of the match, De Groot and Van Koot survived the retaliation from Shuker and Montjane, but once again broke the serve later in the set and rushed through the second to win 6-4 6-1.
“It’s a good combination. It’s fun. We learn too, ”Van Koot explained.
“I think every time we try to set a standard a little higher than the last.”