The 50-year-old Italian came second in her heat in the trials and was proud after her Paralympics debut.
A dream I've had since I was a little girl, she says to The Telegraph.
In the semifinal, however, she didn't make it. Her 57.58 was a personal record, but 1.24 seconds too slow for a final spot.
Valentina Petrillo is the first openly transsexual athlete in the Paralympics.
I'm fighting against the prejudices and discrimination that come with life as a trans person like me, she says according to La Gazzetta Dello Sport.
Petrillo came out as a woman in 2017 and, with the help of hormone treatment, has been able to lower her testosterone levels to levels approved for competing as a woman in the Paralympics.