American sprinter Ronnie Baker set the fastest 100m time of the season by clocking 9.87 seconds to win at the Chorzow meeting in Poland.
It meant the 24-year-old lowered his personal best, as well as the season's best of 9.88 he shared with compatriot Noah Lyles.
His time also eclipsed Usain Bolt's previous meeting record of 9.98, which was set in 2014.
"I felt ready," said the world indoor 60m bronze medallist.
Baker will have the opportunity to win the Diamond League title in Brussels on 31 August.
He triumphed over 100m in the Rome, Paris and London legs to lead the standings going into the final.