American record holder Tyson Gay ran the year's fastest 100 metres when he clocked 9.79 seconds in a tune-up meet at Clermont, Florida on Saturday.
The performance came hours before Jamaican training mate Steve Mullings sprinted 9.80 at the Prefontaine Classic Diamond League meeting in Eugene, Oregon.
Mullings held the yearly lead of 9.89 before Saturday's performances.
Gay's time came in a preliminary race at the NTC Sprint Series. He did not compete in the final, according to official results.
Both his and Mullings' performances were with allowable winds.
Jamaican Usain Bolt holds the world record of 9.58 seconds. Gay's U.S. record is 9.69.
The American is scheduled to make his Diamond League debut with another 100 metres at the New York Grand Prix next Saturday.