World number one Ashleigh Barty fell in the US Open third round to a tight three-set defeat by Shelby Rogers in front of a raucous New York crowd.
Wimbledon champion Barty held a 5-2 lead in the final set and twice served for the match but home favourite Rogers battled her way back into contention.
The world number 43 then came through the resulting tie-break to stun the top seed 6-2 1-6 7-6 (7-5).
She will face British teenager Emma Raducanu next.
Barty was devoid of rhythm in the first set but seemed to have found, if not her best form, enough to take her into the fourth round.