After the two sides lost to leaders Sweden in the opening week, it now comes down to a straight head-to-head to seal safe passage into the last eight.
In the immediate wake of a shock defeat to these Games' stand-out stars so far, the USA bounced back to recapture their traditional swagger and style in their second group game, against New Zealand.
Just days after Sweden had hit the headlines with a dominant 3-0 win over Vlatko Andonovski's team - which had enjoyed a phenomenal 44-game unbeaten run coming into the summer's main event - the USWMNT picked themselves off the canvas to stay within a win of guaranteeing a previously assumed place in the next stage; something which they have never failed to do at the Olympics.
Andonovski's normally dominant outfit may have found themselves overrun during his first defeat at the helm, but emphatically returned to winning ways by thumping New Zealand 6-1 in Saitama.
World Cup star Rose Lavelle and Portland Thorns midfielder Lindsey Horan gave the US a 2-0 half-time lead, with the latter marking her 100th cap in style as her teammates ruthlessly added four more after the break.
Having kick-started their bid for a fifth gold in seven attempts - in the process posting their largest-ever margin of victory in an Olympic Games fixture - the four-times world champions now need another characteristically fearless 90 minutes on Tuesday, as they face a competitive Australia side.
Though they were pleased to pick up a positive result in their first game of the tournament by beating regional rivals New Zealand, at the weekend, Australia were brought back down to earth with a bump.
While victory would have effectively put them through to the quarter-finals, the Matildas were felled by an increasingly impressive Sweden side which ultimately deserved to win an entertaining encounter.
The Swedes were forced to do it the hard way, however, after Australia went 2-1 ahead early in the second half and looked set for all three points.
Chelsea striker Sam Kerr's second goal of the game put her team in front after 48 minutes, after they previously trailed by a goal themselves. However, the prolific poacher will undoubtedly rue a failed attempt from the penalty spot 20 minutes later, which could have pulled the score back to 3-3, before Sweden ran out 4-2 winners in the end.
Having been beaten by his compatriots in Saitama, the Matildas' Swedish coach Tony Gustavsson must now quickly rouse his troops, as they face arguably the toughest challenge in women's football next up.
Certainly, the 2023 World Cup co-hosts will be underdogs against the winning machine that is the USWNT, but it has at least been proven that they are not entirely unbeatable.
Vlatko Andonovski made a series of changes to the USA's vastly experienced lineup last time out, with stalwarts Carli Lloyd and Megan Rapinoe both being drafted into the starting XI, while Julie Ertz was brought in to bolster the midfield.
Ertz's progress had been monitored for months ahead of the Games after she sustained an MCL sprain in May, and as a mainstay since 2015, her presence offers authority to the US engine room.
For Australia, meanwhile, star striker Sam Kerr will lead the line, as she closes in on Lisa De Vanna's national goalscoring record. Former NWSL forward Kerr is currently three goals short of the mark after narrowly missing out on a hat-trick at the weekend.
Tony Gustavsson generally sets the Matildas up in a 3-4-2-1 formation, which may have to operate more like a five-woman back line at times, as either young Teagan Micah or experienced Arsenal goalkeeper Lydia Williams - both of whom have started one match so far - is sure to need protection from the USA's fearsome attacking unit throughout.
USA Women possible starting lineup:
Naeher; O'Hara, Dahlkemper, Sauerbrunn, Dunn; Lavelle, Horan, Ertz; Rapinoe, Lloyd, Heath
Australia Women possible starting lineup:
Williams; Catley, Polkinghorne, Carpenter; Yallop, Luik, Van Egmond, Raso; Foord, Simon; Kerr
We say: USA Women 2-1 Australia Women
Following the end of their excellent unbeaten run, the world champions quickly recovered from an opening day slip-up and can continue their return to winning ways against the Matildas.
While cracks are starting to show in an ageing squad, the US just have too many attacking talents for Australia to repel on Tuesday, so will make it through to the quarters - with the Aussies keeping fingers crossed they have done enough to progress as a third-placed side.
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