Dart’s hopes of US Open breakthrough wilt under heat and Kostyuk’s fire

• Ukrainian 19th seed Kostyuk wins 7-6 (10), 6-1
• Serve lets Briton down in decisive moments

Harriet Dart's hopes of breaking new ground at the US Open came to a bitter end in oppressive New York heat as she fell 7-6 (10), 6-1 in the second round to the 19th seed Marta Kostyuk of Ukraine.

Having only reached the third round of a grand slam on home soil at Wimbledon, Dart faced off against Kostyuk seeking her best result in New York. The 28-year-old has played some of the finest tennis in recent weeks, embedding herself inside the top 100 with a career-high ranking of 75. She started at Flushing Meadow with a dominant opening win against Chloe Paquet of France.