Complex sentence: He fought 38 times as a professional in a career that spanned 10 years from 1984 to 1994, with 34 wins by knockout and only one loss, that being to Lennox Lewis when he challenged for the European title in 1991.
Split into simpler sentences: He fought 38 times as a professional in a career that spanned 10 years from 1984 to 1994 and lost only one bout. His solitary loss was to Lennox Lewis when he challenged for the European title in 1991.