Goals from Rose Lavelle, Lindsey Horan, Christen Press and Alex Morgan, as well as two own goals, sealed the victory for Vlatko Andonovsky’s side.
– Women’s Olympic Games football support and matches
Betsy Hassett netted a consolation goal for New Zealand, but the USWNT put on a stunning performance to secure their first victory at the Olympics.
The United States entered the game looking to recover from the shock loss to Sweden in the opener, which ended a 44-game unbeaten streak.
Lavelle gave the USWNT a perfect start after nine minutes of receiving the through ball from Tobin Heath and produced a compound finish.
Horan believed he doubled the lead after 35 minutes, but his strike was ruled out by VAR for offside.
Just before the break, Horan scored from close range with a header, with Megan Rapinoe providing the assist.
With the team leading 2-0 at the break, United States First Lady Jill Biden arrived in time to see the team put the game aside in the second half.
The Americans scored a third goal after 63 minutes when Abby Erceg headed for her own goal on a shot from Carli Lloyd inside the box.
Nine minutes later, New Zealand took advantage of a poor defense to score thanks to Hassett.
However, the USWNT responded with late strikes from Press and Morgan, plus an own goal from CJ Bott, to seal a comfortable victory.