PARIS — Serena Williams earned a berth in the French Open quarterfinals and extended her career-best winning streak to 28 matches by beating Roberta Vinci 6-1, 6-3 on Sunday.

Williams had her toughest test yet this week but swept the last 10 points and has lost only 10 games in four rounds.

The 15-time Grand Slam champion next plays 2009 winner Svetlana Kuznetsova. With a victory, Williams would earn her first berth in a French Open semifinal since 2003.

She won her lone Roland Garros title in 2002.

Williams improved to 20-0 this year on clay. Since losing in the first round a year ago at Roland Garros, Williams is 71-3, including titles at Wimbledon, the U.S. Open, the London Olympics and the season-ending WTA Championships.

She first reached the quarterfinals at Roland Garros in 2001, when she was 19. Now she’s 31 and the oldest player in the top 20.

The other remaining U.S. women play Monday. Four Americans reached the fourth round, the most at Roland Garros since 2004.

In men’s play, David Ferrer reached the quarterfinals for the sixth Grand Slam in a row by beating Kevin Anderson 6-3, 6-1, 6-1.

Kuznetsova, ranked 39th and unseeded, beat No. 8 Angelique Kerber 6-4, 4-6, 6-3. The Russian has reached the final eight in back-to-back major tournaments for the first time since 2009, when she won the title at Roland Garros.

She reached the quarterfinals at the Australian Open in January before losing to eventual champion Victoria Azarenka.

Kuznetsova whacked a forehand winner on match point, then let out a jubilant scream. The two-time major champion improved to 12-2 this year in three-set matches, and her winning percentage of .820 (41-9) at Roland Garros is the best among active players.

Ferrer, seeded No. 4, converted 6 of 17 break-point chances against Anderson. Ferrer held every service game and committed only 11 unforced errors to 41 for the South African, seeded No. 23.

When the Spaniard closed out the victory, he looked to the blue sky and raised both fists. His next opponent will be the winner of the match between two fellow Spaniards, No. 11 Nicolas Almagro and No. 32 Tommy Robredo.

Ferrer has won four matches without dropping a set. He’s a four-time major semifinalist, including at Roland Garros last year.