Paralympic champion Shingo Kunieda hit 21 winners past Casey Ratzlaff ©Getty Images

Shingo Kunieda began his US Open wheelchair men's singles title defence in style in New York City against wildcard Casey Ratzlaff as the semi-finals for both the men's and women's singles were decided.

The seven-time US Open champion and Tokyo 2020 gold medallist dominated the American in a 6-1, 6-0 straight-sets victory, suffocating Ratzlaff's service game.

The 37-year-old won 91 per cent of points on his first serve whereas his opponent could only manage a 38 per cent ratio.

Second seed Alfie Hewett is in search of his third Grand Slam at the Billie Jean King National Tennis Center.

The Briton overcame a tough first-set challenge against France's Nicolas Peifer to seal a 7-5, 6-2 win.

He will meet Argentine Gustavo Fernández in the semi-finals after he overcame another Frenchman, Stéphane Houdet, 6-4, 6-3.

Hewett's compatriot Gordon Reid is set to face Kunieda in the next round as he defeated The Netherlands' Tom Egberink 6-1, 6-4.

Meanwhile in the women's singles, number one seed Diede de Groot swept aside Angélica Bernal 6-2, 6-0.

Diede de Groot has won the past three US Open women's singles titles ©Getty Images
Diede de Groot has won the past three US Open women's singles titles ©Getty Images

The Colombian all but gifted the Dutch Paralympic champion the match after conceding 11 double faults.

De Groot is the women’s singles defending champion and is looking to complete a calendar Grand Slam, having won all three Grand Slams and the gold medal Tokyo 2020 so far this year.

The result sets up an all-Dutch semi-final after de Groot's compatriot Aniek van Kook beat Dana Mathewson of the United States 6-1, 6-2.

World number two Yui Kamiji of Japan defeated South African Kgothatso Montjane 7-6, 6-2 after a huge first-set tiebreak which ended 14-12.

The last quarter-final saw Briton Jordanne Whiley beat Japan's Momoko Ohtani 6-1, 5-7, 6-3.

The singles semi-finals are set to take place tomorrow and quad singles tournament will also get underway, where Australian Dylan Alcott also seeks the calendar Grand Slam.