Unseeded Italian Roberta Vinci defeated heavy favorite Serena Williams today in the U.S. Open semifinal, winning 2-6, 6-4, 6-4. Vinci, the 43rd-ranked women’s player, has never before reached a Grand Slam final.

It’s Williams’ first loss in a Grand Slam since Wimbledon in 2014 and eliminates the possibility that she’ll become the first tennis player since 1988 to win all four Grand Slam tournaments in one year. This will also be the first time since 2011 that Williams has not won the U.S. Open.

Vinci committed only 20 unforced errors in the match to Williams’$2 40.

The median listing price of women’s Open finals tickets on the SeatGeek site was $1,186 before the match, Fortunereported, as fans anticipated a potentially historic Williams victory. Vinci will now face fellow Italian Flavia Penneta—herself the 26th-seeded winner of a semifinal upset over 2nd-seeded Simona Halep earlier today—in that match.

This post was updated with additional information after being published.