David Wagner secured top spot in his quad singles group at the NEC Wheelchair Singles Masters in Orlando by recording his second consecutive victory.
The home favourite had begun the tournament with a hard-fought three set win against Sam Schroder of The Netherlands.
Wagner's second victory at the United States Tennis Association National Campus was a more comfortable affair.
He saw off the challenge of Australia's Heath Davidson 6-4, 6-1 to top the Group B standings.
Schroder finished in second place in the group.
Group A saw Niels Vink seal first place, as the Dutch player overcame Britain's Andy Lapthorne 6-4, 6-3.
Lapthorne still came second ahead of Japan's Koji Sugeno, ensuring him a place in the knockout stages.
The group stage of the men's doubles competition concluded with Belgium's Joachim Gerard and Sweden's Stefan Olsson achieving a third straight win.
The duo overcame the Americans Chris Herman and Conner Stroud 6-1, 6-0 to finish top of Group A.
Stéphane Houdet and Nicolas Peifer qualified in second place after the defending champions received a walkover in their final group match.
The Netherlands' Tom Egberink and Maikel Scheffers finished top of Group B on sets won, after three teams ended with two wins and one defeat.
The duo won 6-2, 6-2 against Spain's Daniel Caverzaschi and Martin De La Puente today, while fellow Dutchman Ruben Spaargaren and Belgium's Jef Vandorpe were second after beating Britain's Alfie Hewett and Gordon Reid 7-5, 6-1.
In the women's doubles competition, Germany's Katharina Kruger and South Africa's Kgothatso Montjane won 6-3, 4-6, 7-6 against the Netherlands' Marjolein Buis and the United States' Dana Mathewson.
Montjane and Kruger topped the standings ahead after their victory.
Favourites Diede De Groot and Aniek Van Koot of the Netherlands were 6-1, 6-1 winners against Britain's Lucy Shuker and Jordanne Whiley.
The Dutch pairing finished at the top of Group A after winning both of their group matches.
The knockout stage of the competition begins tomorrow.