The USA repeated Thursday’s 3-1 win over Iceland in which the visitors drew level but this time they enjoyed the lead for nearly half the match.
Karólína Vilhjálmsdóttir beat goalkeeper Casey Murphy direct from a corner kick just after the half-hour, to give Iceland a surprise lead.
Lynn Williams eventually got the USA back on level terms in the 72nd minute, after Emma Sears brought down the ball to her.
The turnaround was complete four minutes later when Lindsey Horan netted at the far post from a Williams free kick.
In added time, Sears sealed the victory by finding the roof of the net on her senior debut.
Other international friendly results:
Honduras 1-3 Guatemala
Costa Rica 0-1 Panama
Senegal 1-1 Tanzania
DR Congo 1-2 Uganda
Senegal equalised at the end of the 90 minutes but saw one player sent off in added time, while two Tanzanian players also saw red.