Allyson Felix has won her 11th Olympic medal by combining with her American teammates to finish the 4x400-meter relay in 3 minutes, 16.85 seconds for a runaway victory.
The team of Felix, Sydney McLaughlin, Dalilah Muhammad and Athing Mu was never in jeopardy in this one.
Poland finished second and Jamaica was third.
Felix became the most-decorated woman in Olympic track history when she won bronze in the 400 on Friday.
She now passes Carl Lewis with the most track medals of any U.S. athlete. Seven of her 11 medals are gold.