ALISON RISKE

U.S. singles players got two wins on Day 2 after all four singles entrants who played on Day 1 lost.

Four of the six American tennis players competing on day one of the tennis competition in Tokyo lost.

The Associated Press has learned that teenager Coco Gauff and Australian Open runner-up Jennifer Brady will lead the U.S. Olympic tennis team at the Tokyo Games.

Serena Williams is out of Wimbledon after she stopped playing her first-round match because of a right leg injury.

(AP Photo/Seth Wenig)NEW YORK The Latest on the U.S. Open tennis tournament (all times local):6:40 p.m.Unseeded Americans Ann Li and Shelby Rogers have pulled off upset victories in the second round of the U.S. Open. ___6:05 p.m.Top-seeded Karolina Pliskova has been upset in the second round of the U.S. Open by Caroline Garcia of France. It was the first time since 2008 that the top-seeded woman lost in the second round at the Open. Pliskova was a finalist at the Open in 2016 for the best Grand Slam result of her career. Seeking his fourth U.S. Open title, Djokovic lost a physical first set that took more than an hour.

Julian Finney/Getty Images(CNN) - Serena Williams reached her 12th Wimbledon semifinal with a gritty three-set victory against fellow American Alison Riske on Centre Court Tuesday. So just the keyword is getting fit and getting back into match play injury-free. But Riske's forehand was firing, and she broke Williams immediately, only for her compatriot to break again for 4-4. Williams had several breakpoints in a roller-coaster eighth game and eventually clinched the break when Riske double-faulted. Williams will also team up with two-time Wimbledon men's singles champion Andy Murray back out on Centre Court for their mixed doubles second-round match against Fabrice Martin and Raquel Atawo.

(CNN) - Women's world No.1 Ashleigh Barty couldn't maintain her French Open-winning form and crashed out of Wimbledon to American Alison Riske Monday. The shock result kicked off Wimbledon's blockbuster "Manic Monday" when all 32 remaining men's and women's singles players compete for a place in the quarterfinals. Cori "Coco" Gauff -- the 15-year-old sensation who has taken this grand slam by storm -- continues her remarkable fortnight but faces one of the pre-tournament favorites in Simona Halep, a former world No.1. First up on No.1, seven-time Wimbledon champion Serena Williams will face diminutive Spaniard Carla Suarez Navarro. 3 seed and former Wimbledon champion Petra Kvitova.