ATHLETICS NEWS - Coleman's mark beat the previous record of 6.39 set twice by fellow American Maurice Greene, in 1998 and 2001.
The performance is subject to ratification by athletics' world governing body the IAAF.
"Great start to my career," tweeted Coleman, who aged 21 is in his first full year as a professional athlete.
It beats his previous best of 6.45, which he recorded when he won the US indoor championship last year.