Dufek made an impressive single-seater debut back in 2020, competing in the Spanish Formula 4 Championship. Joshua reached the podium in all but two race rounds, finishing seven times in the top-three classifications.

The year after, the now eighteen-year-old Swiss signed with Van Amersfoort Racing for a double F4 campaign, covering both the Italian and German F4 Championships. Dufek was able to showcase his talent by claiming no less than nine top-three finishes divided over both series, including his first ever F4 race win during the penultimate round of the Italian series at the Mugello circuit in Italy.

As part of his 2022 season preparation, Joshua competed in the first three rounds of the ’22 Formula Regional Asian Championship, collecting valuable experience for the year to come.