The United States have won gold in the women's football events at four of the past seven Olympic Games
The United States, managed by former Chelsea boss Emma Hayes, began their women's Olympic football campaign with an emphatic 3-0 win over Zambia in Nice.
Trinity Rodman hit the crossbar early on before she gave Hayes' side the lead after 17 minutes.
Mallory Swanson scored twice inside a minute to put the United States 3-0 ahead after 25 minutes, with Zambia then reduced to 10 players followed Pauline Zulu's red card.
However, despite having a player advantage throughout the second half, the United States could not stretch their lead further.
This was Hayes' first competitive match in charge of the United States after she left Chelsea at the end of last season following 12 years in charge.
During her time at Stamford Bridge, Hayes guided the Blues to the Women's Super League title seven times, including in each of the past five campaigns.
France, Germany, Brazil and Spain all win opening matches
Highlights - Spain 2-1 Japan
Earlier on Thursday, Germany defeated Australia 3-0 in the other Group B game thanks to goals from Marina Hegering, Lea Schuller and Jule Brand.
The United States take on Germany on Sunday in Marseille and the winner of that will advance into the quarter-finals.
Hosts France also made a winning start, holding off a Colombia fightback to win 3-2.
Two goals from Marie-Antoinette Katoto and one from Kenza Dali put France 3-0 ahead, although a penalty from Catalina Usme and a goal from Manuela Pavi Sepulveda gave Colombia hope.
But they could not force an equaliser and Chelsea striker Mayra Ramirez was sent off late on.
World Cup winners Spain came from behind to beat Japan 2-1 thanks to goals from Aitana Bonmati and Mariona Caldentey after Aoba Fujino had scored the opener.
Brazil defeated Nigeria 1-0 thanks to Gabi Nunes' goal and Canada fought back to beat New Zealand 2-1 despite conceding the first goal.
