Top seed Serena Williams was knocked out of the ASB Classic in Auckland in the second round by fellow American Madison Brengle on Wednesday.
World number two Williams was beaten 6-4 6-7 (7/3) 6-4 by the 26-year-old, who is 70 places below her in the current rankings.
It was the biggest win of Brengle's career and her first against a top-three opponent, with Williams making 88 unforced errors.
"I really think I played - I'm trying to think of a word that's not obscene - but that's how I played," Serena told wtatennis.com after the match.
"Eighty eight unforced errors is too much, just way too many. It's a lot. I can't expect to win hitting that many errors.
"I couldn't get used to the wind; my opponent was playing in the same conditions, and maybe the wind was more suited for her game, but it was really annoying me for whatever reason."
First #WTA career Top 3 win!!
— WTA (@WTA) January 4, 2017
World No.72 Madison Brengle knocks out Serena Williams 6-4, 6-7(3), 6-4! #ASBClassic pic.twitter.com/eSHu1i4mHe
