Perth, Jan 1 : After losing its opening Group C tie against Great Britain, Australia came back strongly to storm into the quarterfinals of the United Cup, beating defending champions the United States in a must-win clash on Monday. Heading into a winner-takes-all mixed doubles clash, Matthew Ebden and Storm Hunter defeated Jessica Pegula and Rajeev Ram 6-3, 6-1 to ensure the home nation topped Group C at the 18-country mixed-teams event. Earlier in the evening, Alex de Minaur boosted Australia's United Cup quarterfinal hopes when he overcame Taylor Fritz 6-4, 6-2 to give Australia a 1-0 lead. World No. 5 American Jessica Pegula then defeated Ajla Tomljanovic battling past the Australian 7-6(6), 6-3 and sending the tie to a deciding mixed-doubles match. Matthew Ebden and Storm Hunter walked onto the court inside a packed RAC Arena needing to win in straight sets to reach the quarterfinals. After a dominant first set, they rallied from a break down in the second set to advance after one hour and two minutes. In earlier singles action, Pegula faced down Tomljanovic to come back from a precarious deficit in each set to engineer her first win of the season. After failing to hold on to an early break in the opening set, Pegula found herself facing set points to Tomljanovic as she served down 5-4. The American quickly tapped into her trademark fighting qualities, wiping out three set points with courageous serving to hold. Little separated the two in the tiebreak, but Pegula edged ahead at 6-5 to earn her first set point. Tomljanovic, who spent the bulk of the 2023 season on the sideline due to injury, kept Pegula in the extended set, saving two set points before finally relenting after 63 minutes. Tomljanovic did not let her disappointment linger. She broke Pegula early in the second set and built a 3-1 lead before the American once again fought her off. Though she struggled to find her trademark consistency throughout the match, Pegula found her best ball-striking when it mattered. She clawed her way back from a break down to reel off four straight games to close out the physical one-hour and 52-minute encounter. Earlier, de Minaur boosted Australia's hopes of reaching the last-eight stage when he overcame Fritz 6-4, 6-2 to give the home nation a 1-0 lead in its Group C tie against the United States. /IANS