Stephens downs Muguruza to reach French quarters

   Sloane Stephens took a big step today toward her second consecutive French Open final.
   In a matchup of former Grand Slam champions, the seventh-seeded Stephens beat 19th-seeded Garbine Muguruza 6-4, 6-3 to reach the quarterfinals in Paris.
   Stephens, a 26-year-old Fresno product and the 2017 U.S. Open champion, improved to 2-1 against Muguruza, who won the French Open in 2016 and Wimbledon in 2017.
   Muguruza also captured the doubles title in the 2014 Bank of the West Classic with fellow Spaniard Carla Suarez Navarro.
   Stephens, who lost to Simona Halep in last year's French Open final after leading by a set and early service break, is scheduled to face 26th-seeded Johanna Konta of Great Britain on Tuesday.
   Konta, the runner-up in two clay-court tournaments this spring (Rome and Rabat), eliminated 23rd-seeded Donna Vekic of Croatia 6-2, 6-4.
   Konta, who won the 2016 Bank of the West Classic, is 2-0 against Stephens. Both matches occurred this year, with Konta triumphing 6-7 (3), 6-4, 6-1 in the second round in Rome 2 1/2 weeks ago and 6-4, 6-3 in Brisbane in January in the first match of the year for both players.
   In the other quarterfinal in the bottom half of the French Open women's draw, 31st-seeded Petra Martic of Croatia will play unseeded Marketa Vondrousova, a Czech left-hander who will turn 20 on June 28.
   Of the top five seeds, only No. 3 Halep remains on the women's side but all are still alive on the men's side.
   The men's quarterfinals will feature a matchup of Swiss former French Open champions, third-seeded Roger Federer and 24th-seeded Stan Wawrinka.
   Federer, who won Roland Garros 10 years ago, dismissed unseeded Leonardo Mayer of Argentina 6-2, 6-3, 6-3. Federer, 37, has not lost a set in four matches in this year's tournament.
   Wawrinka, the 2015 French Open champion, outlasted sixth-seeded Stefanos Tsitsipas, a 20-year-old Greek, 7-6 (6), 5-7, 6-4, 3-6, 8-6 in 5 hours, 5 minutes.
   Second-seeded Rafael Nadal, seeking his 12th French Open singles title, will meet either seventh-seeded Kei Nishikori of Japan or unseeded Benoit Paire of France. Nishikori, a two-time French Open quarterfinalist, leads 6-2, 6-7 (8), 6-2 in a match suspended by darkness.