Winnipeg Arena, which stood on the north end of the mall site, predated the shopping hub by 4 years. It served as the home venue for the Winnipeg Warriors, Winnipeg Jets and Winnipeg Monarchs hockey franchises. The structure was demolished in March 2006.
Photo from Wikipedia / "JETStender"

A mid-1960s view of the south end of POLO PARK CENTRE. The open-air complex had been enclosed and heated in 1963-1964.
Photo from University of Manitoba, Winnipeg Building Index

By 1969, the two supermarkets on the north end of POLO PARK had been relocated to the east side of the centre. The original locations were sectioned into inline spaces and an Eaton's department store built. The mall now housed over sixty stores and services.