American teenager Coco Gauff delighted the home fans by reaching her first US Open semi-finals with a 6-0 6-2 victory over Iga Swiatek's conqueror Jelena Ostapenko on Tuesday.

Gauff, whose lead-up to the US Open included hardcourt titles in Washington and Cincinnati, converted six of her seven break points and dropped serve just once during the 67-minute match on a sun-drenched Arthur Ashe Stadium.

The 19-year-old is the first American teenager to reach the final four at Flushing Meadows since Serena Williams was the runner-up to her older sister, Venus, in 2001.

Up next for Gauff will be Czech 10th seed and French Open finalist Karolina Muchova after she hammered 31 winners in a comfortable 6-0 6-3 victory over Romanian 30th seed Sorana Cirstea.

With her win, Muchova became only the second Czech player to reach the women's singles semi-final at Roland-Garros and the US Open in a calendar year, after Helena Sukova in 1986.