Later in the day, Ehrlich denied that he had been disturbed by the presence of Democratic politicians. "If I had a problem with that, I wouldn't run in this state," he said.
Ehrlich, who has slipped behind O'Malley in recent weeks after a summer of polls showing the race in a dead heat, tried to use the format to his advantage, striking a more conversational demeanor.
O'Malley talked primarily to the camera, repeatedly accusing Ehrlich of cutting spending to schools and higher education during better economic times — charges the former governor did not refute.
The candidates' tempers flared as they discussed education, specifically in Baltimore. Ehrlich called a 2006 battle over whether the state should step in to oversee 11 failing Baltimore schools "disgusting" and said it was "one of the worst episodes I've seen of protecting a monopoly."
As governor, Ehrlich negotiated a funding package that included state oversight, but it was rejected by the Democrat-controlled General Assembly.
O'Malley accused his opponent of speaking in "very coded language about kids that aren't succeeding." The governor added, "I'm tired of people putting down the achievements of poor children and children of color."
Ehrlich lambasted his opponent's "demagoguery" on the college tuition freeze, and pointed out that room, board and other fees had increased in the past four years. That poses a struggle for "working class folks like I come from," Ehrlich said.
O'Malley pointed out that the fees had risen under Ehrlich and chastised his predecessor for endorsing a tuition freeze only as the 2006 gubernatorial contest drew near. Ehrlich did not sign the freeze legislation but let it become law.
The two differed sharply on the use of employee furloughs to help balance the state's budget. Ehrlich said furloughs, which are unpaid days off, "demoralize" workers while O'Malley countered that they were preferable to mass layoffs.
The Republican candidate chided his opponent for being overly reliant on federal stimulus funding to balance the state's budget.
O'Malley countered, "You never turned down a single dollar from the federal government when you were governor."
After the debate, O'Malley said it was a "lovely exchange of ideas."
"I believe the people of our state understand what's at stake here," he said. "In much easier times, the former governor made the wrong decisions. In the toughest of times we made the right decisions to move the state forward."
Ehrlich declined to talk to reporters afterward, saying he would take "no questions right now," but adding he was "happy, very happy" about the performance.
After a second appearance Monday with O'Malley at the Maryland Disabilities Forum in Linthicum Heights, Ehrlich praised the WJZ setup.
"What you saw this morning was a terrific format," he said. "People get to see what you're about, what your views are on the issues."
O'Malley's campaign staff sent a flurry of "fact checking" e-mails as the Monday debate unfolded, in addition to two news release declaring the governor "won" before Ehrlich's camp made the same claim.
Ehrlich later said he considered the debate a victory, in terms of "engaging the issues and substantively addressing some of the ads," but added, "Of course I'm sure Martin would say the same thing."
Baltimore Sun reporter Julie Scharper contributed to this article.