The perfect match came in the second round on Zurich's largest square, Sechseläutenplatz, where today's six Diamond League finals have been moved.
The remaining 26 finals will be decided inside Letzigrund during the day.
World champion Crouser chased Kovac's giant shot but had to settle for 22.74 (competition ongoing).
At the WC in Eugene six weeks ago, Crouser won in 22.94 to Kovacs' 22.89.
It was the first time that Kovacs was over 23 meters.