AP Photo/Lynne Sladky

KEY BISCAYNE, Fla. (AP) — Serena Williams’ 20-match winning streak at Key Biscayne ended Monday with a 6-7 (3), 6-1, 6-2 loss to Svetlana Kuznetsova in the fourth round of the Miami Open.

Williams was bidding for her ninth title in the event and her fourth in a row. But after a grueling first set that lasted nearly an hour, the No. 1-seeded Williams faded on a sweltering afternoon.

The No. 15-seeded Kuznetsova won with defense, extending points until Williams would make a mistake. The Russian finished with only 18 unforced errors to 55 for Williams.

Kuznetsova improved to 3-8 against Williams and beat her for the first time since the 2009 French Open quarterfinals.

Williams still hasn’t won a tournament since earning her 69th title at Cincinnati in August.