Justin Gatlin ran 9.93 seconds to win the 100m at the Daegu Championships in South Korea on Wednesday.
The former Olympic champion followed up his 9.87secs clocking in Doha last week with another sub-10s run.
The 30-year-old, who served a four-year drugs ban from 2006-2010, finished well ahead of the field, with fellow American Mike Rodgers second in 10.06.
Usain Bolt leads the rankings this year with 9.82.
