Mattias joined the club in 2020 through an international transfer and started his Chelsea handball career on the concrete courts outside Bosco, thinking proper handball courts had evaded the country with Brexit.

Contrary to common misconceptions, Mattias is not of Swiss origin, yet on the handball court, his defending is akin to the precision of Swiss clockwork. Hailing from a rich blend of French and German heritage, he seamlessly fuses German organizing skills in defense with French flair in offense.