UPDATE, 3/28/2018: Today, the IAAF announced that Christian Coleman's world-record 60m mark of 6.34 has officially been ratified!

It's difficult enough to break a world record over the course of a lifetime. But Christian Coleman has done it twice in the span of a month.

En route to winning today's 60m final at the 2018 USATF Indoor Championships, Coleman shifted to another gear in the last 20 meters to cross the line in 6.34 seconds—even faster than the 6.37 he ran at the Clemson Invitational in his January season opener, which ultimately wasn't ratified as a world record due to the lack of electronic starting blocks and on-site drug testing.

Now, Coleman will officially be the fastest man over that distance, taking the mantle from Maurice Greene, whose 6.39 world record has stood since 1998.

Runner-up Ronnie Baker, who almost dipped under Greene's former world record in tandem with Coleman by finishing in 6.40, will round out the U.S. 60m world team heading to Birmingham, U.K., in March. 

Coleman and Baker's times are the fastest and second-fastest marks in the world this year, respectively.

Coleman reacts to the world record:

FINAL RESULTS: