LaShawn Merritt has claimed that he is already targeting victory in the next major athletics competition after exiting the 400m at the Olympics.

The American was forced to pull up in his heat after appearing to aggravate an Achilles injury at the beginning of the race and the Olympic champion admits that his preparations for the Games have been disrupted by the problem.

Merritt told BBC Sport: "I have spent countless hours of treatment, from around 8am to 10pm. I hurt myself in the last race in Monaco but I thought I could get through.

"I am still young, have a long career ahead of me but there was no reason to push it today. I need to rest now and get ready for the world championships next year."

Earlier in the day, Oscar Pistorius booked his place in the semi-finals of the event by finishing second in his heat.