Arriving to Salou on Spain's west coast, Černý and Joona were tied on points with two wins and two runner-up results apiece, setting up a winner-takes-all showdown.
Czech driver Černý delivered the first blow in the all-Ford Fiesta Rally3 category, claiming the opening stage by 16.1sec. However, Joona wasted no time in biting back, winning the next six stages before the final test of the day was red-flagged.
The pairing have opened a healthy gap over the remainder of the field with Paraguayan youngster Diego Dominguez 1min 32sec behind Joona and 4min 54sec ahead of Zoltan László, who rounds out the field.
Finland
Italy
Hungary