Prechampionships the Russian duo were expected the dominate and little has changed to alter that opinion after tonight's semi-finals.
The world's fastest woman this year Olesya Zykina slugged out victory in the first semi-final from the front. Passing halfway in 24.02 from US Championship runner-up Moushaumi Robinson, Zykina, the 2002 European outdoor 400m champion held on down the home straight to win in 51.75.
However, Ukrainian Antonia Yefremova, who was some five metres back at the bell, showed enough in the second lap pace to suggest she could be a danger in the final to snatch second just 0.04 behind the Russian in a new personal best of 51.79.
Robinson, too, clocked a new lifetime best of 51.85 to book her spot in tomorrow night's final.
In the second semi-final the two-time former champion Natalya Nazarova of Russia dominated from the outset and held a clear lead at halfway in 24.19.
The second half of the race looked fairly routine as she strided out to victory in 51.62 from American champion Shareese Woods, who registered a new personal best of 51.87.
Angela Morosanu of Romania secured the third and final qualifying position from then semi-final with 52.83.
Steve Landells of the IAAF