Ka cika wannan jumla: A lokacin da yake da shekara 15, Markešević ya kafa tarihin kasar na mita 3000 don rukunin shekaru 15 da lokaci na 8:51.58. Markešević ya fara halartar wasannin kasa da kasa a gasar wasannin Olympics ta Turai ta 2003 a Paris, Faransa, inda ya zama na biyu a tseren mita 3000. A cikin
2005 IAAF World Cross Country Championships, Markešević ya gama a matsayi na 36 na masu tsere 125 a tseren 8K na matasa. A ƙarshen wannan shekarar, ya gama na uku a cikin tseren maza na matasa a gasar zakarun Turai ta 2005. A gasar zakarun Turai ta 2006 a tseren tseren tseren, Markešević ya kasance na biyu a gaba ɗaya a kan filin U23 mai matukar gasa, yana gamawa gaban Daniele Meucci da Yevgeny Rybakov.