Stephens suffers another early loss

U.S. Open champion

Sloane Stephens continued her tendency for all-or-nothing showings at tournaments, losing 2-6, 6-4, 6-2 to 91st-ranked

Andrea Petkovic in the second round of the Citi Open at Washington.

The second-seeded Stephens’ best results this season were a runner-up finish at the French Open and a title at the Miami Open. But take away those tournaments, and the American is 10-11 in 2018, including first-round exits at Wimbledon and the Australian Open.

Stephens' loss leaves the Citi Open women's draw without either of its top two seeds; No. 1 Caroline Wozniacki withdrew Tuesday because of a leg injury. On the men's side,

Andy Murray continued to work his way back from hip surgery by beating No. 4 seed Kyle Edmund 7-6 (4), 1-6, 6-4 in the second round for Murray’s first victory over a top-20 player in more than a year. No. 5 seed Nick Kyrgios withdrew because of an injured left hip.

Benoit Paire's racketbreaking tantrum on Tuesday night cost him $16,500 in fines levied by the ATP — more than twice his prize money at the tournament. Paire repeatedly spiked and threw rackets in his 6-3, 3-6, 6-2 first-round loss to Marcos Baghdatis. In other news: • Top-seeded Garbine Muguruza withdrew with an arm injury, opening the way for Victoria Azarenka to beat Muguruza’s replacement, Anna Blinkova 6-1, 6-0 in the second round of the Mubadala Silicon Valley Classic at San Jose, Calif.