Femke Bol won the 400 meters hurdles at the Diamond League match in Florence on Thursday in a new national record.
De Amersfoortse recorded an impressive time of 53.44 seconds.
Sifan Hassan was the fastest in the 1500 meters.
The 21-year-old Bol dived more than three tenths of a second below her own national record of 53.79 seconds, which she ran at Papendal last July.
So far this season she has stuck at 54.33 seconds.
With the fast time on the 400 meter hurdles, Bol was no less than 0.75 seconds faster than the number two, the Ukrainian Anna Ryzhykova.
The British Jessica Turner came in third and had to give in one and a half seconds to the Dutch.
Bol is in top form on her way to the Olympic Games in Tokyo, where she only competes in the 400 meters hurdles.
Two weeks ago she already set a new national record in the 400 meters in Oordegem, Belgium.
Last week she also won the 400 meters hurdles at her debut at the FBK Games in Hengelo.
She clocked 54.33 in her first race of the year in the 400m hurdles.
Only the American Shamier Little (53.12) was faster than the Amersfoortse this year.
With 53.44 she is now third in the world ranking of fastest times this season.