Olympic champion David Rudisha is through to the final of men's 800m final at the World Athletics Championships after winning his semi-final.

The Kenyan, who has been blighted by injuries in the build-up to Beijing, led from the front, but needed a sprint finish to make sure of his place.

However, world number one Nijel Amos is out after he could only take third in the same heat, as Qatar's Musaeb Balla held onto the second qualification spot.

After a blanket finish in heat one, Adam Kszczot and Alfred Kipketer progressed by right. Mohammed Aman of Ethiopia was set for a fastest loser's spot after finishing only 0.04s behind the Polish runner.

However, the defending champion was disqualified after jostling with Dutch athlete Thijmen Kupers before the end of the race.

Marcin Lewandowski is also out of the competition after he was ran out of the automatic qualification places in the final heat.