The Blue Demons (2-3) will play Purdue in the fifth-place game Wednesday. The Boilermakers (3-1) beat Oklahoma 74-71 earlier Tuesday.
Stewart Kussler had 21 points for Chaminade, the Division II host of the eight-team tournament, while Zack Whiting had 13 points and 13 assists, his second straight double-double.
DePaul lost 87-81 to No. 20 Kentucky in the opening round, while the Silverswords were beaten 88-63 by No. 5 UCLA.
Unlike their opening-round loss when UCLA jumped to a 17-2 lead, the Silverswords stayed close in this game into the second half, trailing by one point with 15:46 to play.
Chaminade (0-2) hit three 3-pointers in a 13-4 run to open the second half and was within 50-47. The Silverswords made their first six shots of the second half and got within 52-51 4:14 in on a layup by Kussler.
DePaul then scored 14 straight points as Chaminade came up empty on nine straight possessions, missing five shots and committing four turnovers.
Mejia hit two 3s in the run and capped it with a three-point play that made it 66-51 with 10:27 left.
The Blue Demons went on to lead by as many as 22, the last time at 85-63 with 4:05 to go on a 3 by Draelon Burns.
The Silverswords dropped to 4-62 in their 23 years of hosting the tournament. Two of the wins have been against teams from the Big East, DePaul's conference. They beat Providence 111-108 in 1991, and defeated Villanova 52-49 in 2003, both first-round wins. The other wins were over Davidson (1984) and Stanford (1992).
The win was the 200th for Jerry Wainwright, who is in his 13th season as a head coach. He was at North Carolina-Wilmington for eight years, Richmond for three and is in his second season at DePaul. His overall record is 200-161.
Official Box Score
DePaul Cruises to Wainwright's 200th Victory
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