The loss -- which stopped the Colonels' win streak at four -- wasted a chance for the Bartow school to knock the Grizzlies out of sole possession of third place in Region 7-AAAA.
"We came out very flat and didn't swing the bat well," head coach Todd Eubanks said. "We didn't show up, and we have to do a better job of coaching to get our boys ready.
"Creekview didn't get a cheap hit. They swung the bat well and did the little things that we didn't do. We have to show up better Wednesday (against South Forsyth) and just see what happens."
The Colonels fell behind early as the Grizzlies took a 2-0 lead in the first inning then steadily added to it until they were up 8-0 lead after five innings.
The Colonels added their only run in the top of the sixth inning when Connor Law scored on an RBI single from pitcher Dalton Weightman.
Weightman took the loss for the Colonels, giving up six earned runs in four innings of work. He gave up nine hits and walked one. Brandon Etheridge threw two innings, allowing one earned run while striking out three and getting tagged for two hits.
Law went 1-of-4 with a single while Weightman was 2-of-3 with two singles; Tyler Gates was 1-of-3 with a single; and Dalton Parham drew three walks. The Colonels were charged with three errors.
Reagan O'Briant was credited with the win for Creekview, going the distance and allowing one earned run while walking five.
Cass dropped to 9-6, 5-4 in the region with the loss. Creekview improved to 9-6, 7-2.
Cass next plays against South Forsyth, which it hosts Wednesday at 5:55 p.m.