Complex sentence: Jeffrey "Jeff" Horn (born 4 February 1988) is an Australian WBO welterweight title since July 2017, winning the title by defeating Manny Pacquiao in an upset decision win.
Split into simpler sentences: Jeffrey "Jeff" Horn (born 4 February 1988) is an Australian professional boxer. He has held the WBO welterweight title since July 2017, winning the title by defeating Manny Pacquiao in an upset decision win.