At the lap after 200 meters, Bengtström turned in first and pressed to keep the closest chasing Briton James Williamson behind him in the fourth of nine heats.
With 46.56, Bengtström was 0.21 over his best indoor time from earlier this winter.
- His effort grows for each heat.
The way he ran impressed him by immediately taking command, says SVT Sports expert Alhaji Jeng.
In the sixth heat, the Dutchman Tony van Diepen won, also good in the 800 meters, in 46.54.
In heat number seven, the Frenchman Thomas Jordier won in 46.51 on light legs.
Jesper Hellström went to the final in three steps as the eighth and last man after jumping 16.28 in his third qualifying jump, which was three centimeters on the right side. He sank to his knees during the measurement and could then see that the centimeters were on the right side.