Merritt targets Johnson's 400m world record

By George Scott, Sportsbeat

LASHAWN Merritt insists his work is not done despite adding the 400m world title to his Olympic crown - and already has his eye on breaking Michael Johnson's world record next year. 
 

NUMBER ONE: LaShawn Merritt has left American rival Jeremy Wariner trailing in his wake this year - and intends to do the same in 2010

Merritt captured gold in Berlin ahead of American rival Jeremy Wariner - who he beat to the Olympic title in Beijing - in 44.06 seconds. 
 
The Virginia-native clocked 43.75, a personal best, in China to put him fifth on the 400m all-time list, with Johnson's mark standing at 43.18.