Matej Krumpeštar was one of the pioneers in his sport at world championships . He first took part in the premiere of the World Cup in 1998 in Cogne , where he won the bronze medal alongside Peter Koprivnikar and Iztok Prelog behind the representatives from Italy and France as the starting runner of the Slovenian relay. In 2002 he won the relay silver medal with Andrej Zupan, Rok Rant and Boris Andrejka as the final runner in Pokljuka, home . In 2003 he won the bronze medal in Krün with his teammate Andrej Zupan,Ivan Maradin and Vid Vončina behind Russia and the Ukrainian relay, with Krumpestar again being the last runner. In 2004 he won the silver medals behind the Russian relay in Pokljuka with Jože Poklukar , Gaber Lah and Andrej Zupan as final runners, and in Forni Avoltri in 2005 with Andrej Zupan, Jaka Marinšek and Vid Vončina as starting runners. In 2004 he was also 16th in the sprint, 12th in the pursuit and eleventh in the mass start race. Krumpestar is one of the few athletes who took part in both the first and the last World Championships in the sport.
Krumpeštar achieved the greatest success of his sporting career as an archer. At the 1996 Summer Olympics in Atlanta , he came to two missions. In the individual he was 64th, in the team with Peter Koprivnikar and Samo Medved fifth.