Complex sentence: The highlight of his career was defeating Hale Irwin in a playoff in a Champions Tour event at the 1999 BankBoston Classic thus depriving Irwin the chance to match Chi Chi Rodriguez's record of three straight titles.
Split into simpler sentences: The highlight of his career was defeating Hale Irwin in a playoff in a Champions Tour event--the 1999 BankBoston Classic. With his win, McGinnis deprived Irwin of the chance to match Chi Chi Rodriguez's record of three straight titles.