The 24-year-old Olympic champion bested her own mark of 50.68 seconds set two years ago at the same Hayward Field track.

“Honestly praise God,” she said in televised remarks. “I’m just amazed, baffled and in shock.”

McLaughlin-Levrone exploded out of the blocks and took the lead immediately, soaring over each hurdle in a technically flawless performance.

She was several metres clear of the rest of the field as she crossed the finish to thunderous applause from the crowd in the heart of American track, smiling in a subdued celebration as she punched her ticket to Paris.

Anna Cockrell (52.64 seconds) was second while Jasmine Jones (52.77 seconds) took third.