Dallas, which is playing without star forward Dirk Nowitzki, is back over .500 at 6-5.
"We're going to start calling people out and challenging them," Marion said. "If they buckle, they'll buckle. But if they don't buckle, you'll see what happens."
Marion, who scored 10 points, made his second straight start after sitting out five games with a sprained left medial collateral ligament. He had two points and seven rebounds in Dallas' 103-83 loss at Indiana on Friday.
The Cavaliers dropped the last four and five of six on an 11-day road trip. Cleveland was coming off a 114-101 loss at Brooklyn on Tuesday night, a defensive effort that disappointed coach Byron Scott. Anderson Varejao (35) and Irving (34) both set a career high for points in that setback.
The Cavaliers were 29th in the NBA in points allowed (104.8) entering the game. Cleveland has two rookies and five second-year players on its roster, but Scott doesn't want to hear any excuses.
"Young is a cop-out," he said. "We're still basketball players."
Cavaliers rookie center Tyler Zeller returned after missing four games because of a fractured left orbital bone and a concussion. Wearing a mask to protect the broken bone, he had three points and two rebounds in 25 minutes.
NOTES: Mavericks starting F Elton Brand was scoreless in 11 minutes. He missed both shots from the field and had four rebounds. ... Dallas opens a three-game homestand Monday against Golden State. ... Cavaliers F Alonzo Gee missed a free throw in the first quarter after making his first 20 to start the season. ... Cavaliers F C.J. Miles, the team's top free-agent signing, didn't play for the third straight game on a coach's decision.