Kammala wannan jumla: A Wasannin Olympics na 2008 da 2012, ya yi gasa a tawagar kasa a gasar maza; Belgium ta cancanci zuwa gasar Olympics ta 2008 ta hanyar zama na uku a gasar
Gasar Zakarun Turai a Manchester. A wannan gasar zakarun Turai ta 2007, Dekeyser ya bai wa Belgium jagoranci a karon farko a wasansu da Jamus ta hanyar zira kwallaye 3-2 daga bugun kurciya. A wasan farko na Belgium a wasannin Olympics na bazara a Beijing, da Spain, ya sake zira kwallaye daga kusurwa. Belgium ta yi rashin nasara a wasan 4-2. Daga karshe kungiyar ta Belgium ta kammala na tara a Beijing. A shekara ta 2011 Dekeyser ya zama na huɗu tare da Belgium a Gasar Zakarun Turai a Jamus, kuma a wasannin Olympics na bazara na 2012 a London sun gama na biyar. Ya zama mataimakin zakarun Turai tare da Belgium a Gasar Zakarun Turai ta 2013 a gida a Boom.