Ilona Korstin scored 16 points as Russia made the basketball semis with a 70-49 win over the Czech Republic.
Johnson top-scored for the US
The Russians meet defending champions United States on Friday, who routed Greece 102-72 in their quarter-final.
Brazil, led by 27 points, including two late free throws from captain Janeth Arcain, just managed to get the better of Spain 67-63.
They will meet Australia in the last four after they proved too good for New Zealand, winning 94-55.
Lauren Jackson once again led the Australia team with 28 points while Penny Taylor added 12.
Shannon Johnson top-scored for USA with 21 points as the American team stayed on course for their third successive Olympic gold medal.
Greece, backed by a raucous home crowd, were restricted to just 17 points in the second half as their opponents made it six wins out of six.