Walker hit a solo homer, his 35th, and a sacrifice fly.
Walker hit two free throws to tie the score at 70-70 heading into the fourth, and then Boston led for most of the final period.
In the ninth inning, Walker hit a home run, the fourth of the game, to make the score 10-0.
Walker hit 13 home runs, a career high, during the regular season.
Walker hit 12 home runs as a member of the Rockies that year.
Walker hit all 10 of his field-goal attempts and had 12 rebounds.
After two batters were retired, Walker hit his 15th homer.
With the game tied at 29-29 late in the first half, Walker hit a 3-pointer to put Xavier ahead for good.
Walker also hit the ball towards Ramírez in the next at bat.
Walker, a junior, also hit with field goals of 40 and 22 yards.