The North American derby has gone the way of top seeds Team USA as Coco Gauff and Taylor Fritz sealed victory over Leylah Fernandez and Felix Auger-Aliassime in mixed doubles on Sunday going into the early hours with a 1am finish at the United Cup.

Gauff and Fritz came up big against Leylah Fernandez and Felix Auger-Aliassime in the deciding mixed doubles match.

United Cup campaign has started for Team USA and Coco Gauff has started her new season emphatically in a destructive win over Leylah Fernandez 6-3, 6-2 to have Team Canada chasing early on.

World No.3 Coco Gauff looked sharp in her opening win for Team USA at the United Cup, besting Canada's Leylah Fernandez to give the Americans an early lead in Perth.

Coco Gauff continued her hot form to give USA an early lead before Canada levelled the United Cup tie when Felix Auger-Aliassime overcame Taylor Fritz.

The last time the tennis world saw Coco Gauff on the court, she was holding up the WTA Finals trophy with confetti flying through the air. The 20-year-old did not miss a beat in her month away from competition.