LONDON (AP) — Kendra Harrison of the United States has broken a 28-year world record in the 100-meters hurdles by running 12.20 seconds at the London Diamond League meet.

Kendra Harrison of the US  clears the final hurdle as she runs on to win the women's 100 meter hurdles in a world record time of 12.20 seconds during the Diamond League anniversary games at The Stadium, in the Queen Elizabeth Olympic Park in London, Friday, July 22, 2016. (AP Photo/Matt Dunham)

Kendra Harrison of the US clears the final hurdle as she runs on to win the women’s 100 meter hurdles in a world record time of 12.20 seconds during the Diamond League anniversary games at The Stadium, in the Queen Elizabeth Olympic Park in London, Friday, July 22, 2016. (AP Photo/Matt Dunham)

The confidence-boosting run comes after the 23-year-old American failed to make the U.S. team for the Olympics in Rio de Janeiro next month.

Harrison says “not making the Olympic team I was really upset and I wanted to come out here and do what I know what I could have done” in Rio.

Speaking on the Olympic Stadium track in London, Harrison said: “I was coming out here with just vengeance to show these girls what I have.”

Harrison finished ahead of compatriots Brianna Rollins and Kristi Castlin to surpass Yordanka Donkova’s previous mark of 12.21 set in August 1988.