Kammala wannan jumla: Petersen ya ci gaba da gasar Afrika ta Kudu a shekarar 2011 don ya cancanci shiga gasar
2012 PDC World Darts Championship, inda ya fitar da José Oliveira de Sousa 4<unk>3 (ƙafafun) a zagaye na farko don kaiwa 64 na ƙarshe a shekara ta biyu a jere. Petersen ya buga Steve Brown a zagaye na farko kuma ya dawo daga 2<unk>1 a cikin saiti don cin nasara 3<unk>2, kuma ya dawo daga 2<unk>0 a cikin kafafu a cikin yanke shawara kuma ya tsira daga dart daya. Petersen ya ce bayan nasarar cewa "mafarki ne ya zama gaskiya" kuma yana da tabbacin cewa yana da ƙari a cikinsa. Ya buga Gary Anderson a zagaye na biyu kuma ya buga mafi kyawunsa a gaban kyamarorin talabijin. Koyaya, ajin abokin hamayyarsa ya zo kuma ya yi asara 4<unk>2, tare da Anderson yana bayyana bayan wasan cewa "Devon ya zama mai wahala a gare ni". Petersen da kansa ya ce zai "yi aiki tuƙuru kuma ya dawo mafi kyawun ɗan wasa".