Top seeds Shingo Kunieda and Diede de Groot won in straight sets as the US Open wheelchair tennis competitions got underway at Flushing Meadows in New York.
In the men's singles event, Japan's Kunieda got his bid for a sixth US Open crown off to a winning start as he comfortably defeated France's Nicolas Peifer 6-3 6-2.
Second seed Gustavo Fernandez of Argentina also won in straight sets, beating Stephane Houdet 6-4 6-1.
The all-British contest between Alfie Hewett and Gordon Reid was a surprisingly one-sided affair, with Hewett dropping just two games as he triumphed 6-0 6-2 against his compatriot.
The remaining men's singles quarter-finals went to three sets, with Belgium's Joachim Gerard dropping the first set to America's Casey Ratzlaff 6-4, before Gerard bounced back to take the next two sets 6-3 6-0.
In the women's singles, Dutchwoman de Groot triumphed in straight sets against Britain's Jordanne Whiley, winning 6-3 6-4.
Second seed Yui Kamiji of Japan also advanced to the last four as she beat compatriot Momoko Ohtani 6-2 7-6 while Marjolen Buis of the Netherlands beat American Dana Mathewson 6-2 6-1.
In the other quarter-final, Colombia's Angelica Bernal came from a set down to beat Britain's Lucy Shuker 4-6 6-3 6-3, in a match that started outside but was moved indoors due to rain.
In the quad singles top seed Dylan Alcott of Australia beat Sam Schroder of the Netherlands in straight sets, winning 6-2 6-4.
Alcott led calls for wheelchair competitions to be featured at the Grand Slam, after organisers initially announced it would not go ahead, before making a U-turn after pressure from players, who accused them of discrimination.
Second seed Andy Lapthorne of Britain beat American David Wagner 6-2 2-6 6-4, in the other match that was moved indoors due to the weather.
The quad singles is being played over the next four days in a round-robin format.
The semi-finals of both the wheelchair singles and doubles competitions are due to take place tomorrow, while the round-robin stage of the quad singles competition is due to continue.