(Reuters) - American world 100m silver medalist Christian Coleman broke the 60 meters indoor world record on Friday, clocking 6.37 seconds at a meeting in Clemson, South Carolina.

Coleman’s mark eclipsed the previous record of 6.39 seconds set twice by fellow American Maurice Greene, the first time in 1998.

The performance is subject to ratification by athletics’ world governing body the IAAF.

The 21-year-old Coleman, running at Clemson University in his first meeting of the season, had earlier clocked 6.47 seconds in the preliminaries an hour and 40 minutes before the final.

His previous best was 6.45 seconds, which he recorded when he won the U.S. indoor championship last year.

He then ran 9.82 seconds, the fastest 100 meters of 2017, at the U.S. outdoor collegiate title meeting.

Expected to be America’s next great sprinter, he finished behind Justin Gatlin and ahead of world record holder Usain Bolt in the 100 meters at last year’s world championships in London.