The Americans were 41-23 ahead at half-way and kept firm control to set up a gold medal clash against either hosts Japan or 2012 silver medallists France, who play later.

Chelsea Gray added 14 points and Breanna Stewart 12 for the US while Yvonne Anderson scored 15 points to lead Serbia.

It was never going to be easy for the European champions and Rio bronze medallists, with the all-conquering US so dominant they have won eight out of the past nine Olympic titles.

Their only blemishes so far have been a silver medal behind the Soviet Union at the inaugural tournament in 1976 and bronze in 1992.

The victory at Saitama Super Arena on Friday was the Americans' 54th in a row at the Olympics, an incredible streak that began with the 1992 bronze-medal decider and includes a record six straight gold medals and five wins in Tokyo.

Serbia enjoyed a solid opening few minutes, but a US team led by WNBA veterans Sue Bird, Diana Taurasi and Sylvia Fowles quickly found their rhythm.

They raced to a 25-12 first quarter lead with their defense rock solid before faltering when they used their bench early in the second term and the points dried up.

Coach Dawn Staley reverted back to her starting line-up and the baskets started flowing again as they took a 41-23 advantage into the second-half, 20 of the points from inside the paint.

Serbia was shooting below 30 percent from the field and they failed to make up any ground with the US heading into the final stretch with a 59-39 lead, before cruising home.