Complex sentence: The fight was a preliminary to the World Welterweight Title fight between the reigning World Welterweight Champion Harry Lewis, and his frequent opponent Willie Lewis and was probably the most widely covered fight of Hollandersky's early career.
Split into simpler sentences: The fight was a preliminary to the World Welterweight Championship between the reigning champion Harry Lewis, and his frequent opponent Willie Lewis. It was probably the most widely covered fight of Hollandersky's early career.