Dee ihe na-aga n'ihu maka paragraf a - N'egwuregwu Olimpik nke Ọchịchị 2000 na Sydney, Muller gbara asọmpi n'asọmpi igwu mmiri anọ. O nwetara FINA A-ụkpụrụ nke 25.94 (50 m freestyle), 55.82 (100 m freestyle), na 2:00.35 (200 m freestyle) site na South African Nationals na Johannesburg. N'ihe omume mbụ ya, 200 m freestyle, Muller kwụsịrị ọkara ikpeazụ ya na oge nke itoolu nke 2: 00.04. Na mbido nke mbụ, o tinyere oge nke abụọ kachasị ọsọ na ndekọ South Africa nke 1: 59.89. Mgbe ụbọchị atọ gachara, na 100 m freestyle, Muller gbara onye nke isii na ngwụcha na ihe ndekọ dị mma nke 55.19. Na 50 m freestyle
, Muller dere oge nke 26.07 site na okpomọkụ nke itoolu, mana ọ gafeela ọkara ikpeazụ site na 11 nke abụọ. N'ụbọchị ikpeazụ nke usoro ihe omume ahụ, Muller jikọtara ọzọ na Loots, Sarah Poewe, na Charlene Wittstock na 4 × 100 m medley relay. Na-egwu mmiri n'ụzọ efu, Muller gbara ọsọ ahụ na nkewa nke 54.77, ihe ndekọ mba ọhụrụ, mana ndị South Africa kwụsịrị naanị n'ọnọdụ ise na oge ikpeazụ nke 4:05.15.