Jamaica's Usain Bolt is on course to win his third 200m Olympic gold in a row after winning his semi-final in 19.78 seconds.
Two of his main rivals, American Justin Gatlin and fellow Jamaican, Yohan Blake failed to make it to the finals.
Gatlin, clocked 20.13 seconds to place third while Blake, the 2012 Â silver medalist placed sixth on 20.37 seconds.
With the two out, Â America's LaShawn Merritt, who has run 19.74 this year, is likely to pose the biggest challenge to Bolt in the final.
But Bolt believes he can break his world record of 19.19 and could even go under 19 seconds in the final.
"I definitely think I can try for the world record, I definitely feel that," he said. "I need to run efficiently and get into the straight and run the perfect race."
Bolt said he would have a better chance of achieving his goal to run under 19 seconds if he gets a high lane, adding: "If I get a lower lane it's always harder for me to run the corner when it is tighter."
On Gatlin's exit, Bolt told BBC Radio 5 live: "Everybody's in shock. You can tell from the 100m he's getting old. It's a fact the older you get, the rougher it gets to double.
"Next year if I go to the World Championships [in London] I'm not going to double. I'm going to do the 100m and that is it."
Having already clinched the 100m, Â a win will in the 200m race will give him his eighth Olympic gold medal.