Mezue ahịrịokwu na-esonụ: Petersen mepụtara akụkọ ntolite igwu mmiri ya na 1999 Pan Pacific Swimming Championships na Sydney, ebe o tinyere nke anọ na 100 m breaststroke, naanị obere akụkụ dị n'èzí. N'otu afọ ahụ, Petersen ji ọla edo nye South Africa na 100 m breaststroke (1:02.63) na
Egwuregwu All-Africa na Johannesburg.