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.

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.