Saapunki, who competed for the Ounasvaaran Hiihtoseura club , made his international debut at the FIS Cup show jumping in his hometown of Kuopio in January 2008. In the second competition he was ninth in the top ten. In July and August of the same year he reached two third places in junior jumping competitions in Hinterzarten and Zakopane . From October 2008 Saapunki started with the Finnish B-squad in the Ski Jumping Continental Cup .
At the Nordic Junior World Ski Championships in 2009 in Štrbské Pleso , he jumped to 52nd place in the individual competition. In March Saapunki won the junior jumping in Lahti . A little later he won his first Continental Cup points in the two Continental Cup competitions in Kuusamo . At the Nordic Junior World Ski Championships 2010 in Hinterzarten , Saapunki jumped from the normal hill to 39th place in the individual. In the team competition, he and his teammates narrowly missed a medal and finished fourth.
As a result, Saapunki only managed to win points once in the Continental Cup. He ended his international career in August 2008 with three competitions in the FIS Cup and the Continental Cup in Kuopio. On September 15, 2012 he took part in the Finnish Ski Jumping Championships in Lahti and won his first and only Finnish championship with the team.