Myles, who turned 23 on Wednesday, also had four assists after sitting out Tuesday's 80-60 win over IUPUI with a tight hamstring.
Louisville outrebounded the Governors 43-22. The 6-foot-7 Garcia had seven rebounds, despite twisting his right ankle early in the second half.
Dean, who scored 20 points in Tuesday's win, was selected the tournament's most outstanding player.
Maurice Hampton and William Durden each scored eight points to lead Austin Peay (2-7), which shot 30 percent (14-of-47) and lost to Louisville for the third straight season.
The Cardinals were shaky on offense in the first half, shooting 39 percent (9-of-23) and committing 12 turnovers.
Levi Carmichael's 3-pointer with 8:12 left in the opening half gave the Governors a 19-17 lead and prompted a timeout from Louisville coach Rick Pitino.
The Cardinals responded with smothering defense, forcing five turnovers during a 13-0 run over the next 8 minutes.
Derek Wright stole a pass and banked in a 3-pointer at the halftime buzzer to close Austin Peay's deficit to 30-22.
Louisville looked sharper after the break, opening the second half with an 11-3 run. The Governors twice cut the lead to 13, but O'Bannon hit a 3-pointer with 12:07 left to start a 9-1 burst that put Louisville up 54-34.
O'Bannon drew the loudest cheer of the night when he reverse-dunked an alley-oop pass from Myles with 8:53 remaining. Dean's 3-pointer with 8:21 put the Cardinals up 60-38, their largest lead to that point.
Pitino began pulling his starters near the 5-minute mark.
The usually packed Freedom Hall was only half-full after a storm dumped nearly 4 inches of snow earlier in the day.
IUPUI beat New Orleans 72-60 in the consolation game of the four-team tournament named after Pitino's brother-in-law, who died in the Sept. 11, 2001 attack on the World Trade Center.