Usain Bolt fired out a warning to American arch-rival Tyson Gay by scorching to a world-leading time of 19.73 seconds in the 200m at the Paris Diamond League meet on Saturday.
The 26-year-old Jamaican, a two-time Olympic and world champion over the distance, held off the attentions of compatriot Warren Weir to streak past the field in emphatic style.
Edging Gay's season best by one-hundredth of a second was the perfect broadside in the run-up to what promises to be a keenly contested World Athletics Championships in Moscow between August 10-18.
"All is building up towards a great world championships, you will see a big show there, it will be the climax," warned Bolt.
"And I want to be ready for that."
Grenada's Olympic and world 400m champion Kirani James ran a seemingly effortless world leading time of 43.96 seconds, holding off a late surge from American LaShawn Merritt, the man who previously held both titles.
James, who became Grenada's first Olympic medallist in any sport in London, said it was impossible to nail down one thing as essential for winning gold in Moscow. "Weather, shape, conditions, all that will play a role and there will be seven other guys in the final," he said.
"You always need to pay attention to runners like LaShawn - if he were far too ahead, it'd be tough to catch and beat him."
Ethiopian long-distance superstar Tirunesh Dibaba flew to a meeting record of 14:23.68 in the women's 5000m - the seventh fastest of all time behind her own world record.
Dibaba, twice Olympic 10,000m champion and twice world champion at both 5,000 and 10,000m, had compatriot Almaz Ayana for company as she broke with 800m to go, but she was never in danger as she sprinted home.
"With more pacemaking, I could have run even faster," Dibaba said, adding that her Moscow goals were clear. "I want to double at 5 and 10km. And next year to make my marathon debut."
Jamaica's Olympic women's 100m gold medalist Shelly-Ann Fraser-Pryce almost suffered a setback, a savage dip just seeing her edge Nigerian Blessing Okagbare by a hundredth of a second with victory in a season's best of 10.92 seconds.
Francine Niyonsaba of Burundi, 20, underlined her early-season form in winning the women's 800m in 1:57.26.