Flacco produced two scores in an abbreviated appearance, and the Ravens' defense held Carolina without a touchdown in a 17-12 preseason victory Thursday night.
Flacco went 8 for 12 for 120 yards and a TD. He guided Baltimore to a field goal in his first series, then went three-and-out before directing a 96-yard drive that ended with a 30-yard touchdown pass to Mark Clayton.
"We need to clean some things up, but overall it was a good start," Flacco said.
The Panthers, conversely, stumbled from the outset and never recovered. Starting quarterback Matt Moore -- hindered by poor protection and three penalties against left tackle Jordan Gross totaling 25 yards -- failed to produce any points during his three possessions.
Backup Jimmy Clausen went 8 for 15 for 80 yards and an interception in his informal NFL debut. He was sacked twice.
"There were good things that happened and definitely some things I need to work on," the rookie said. "But overall it was good to get out there with bullets flying around for the first time."
Carolina turned the ball over on a fumble at the goal line by running back Tyrell Sutton that Baltimore recovered on its own 1.
"I thought offensively we killed ourselves a little bit with some penalties, the fumble down at the 1," coach John Fox said. "I thought we moved the ball efficiently. We hurt ourselves some, but we had a lot of young guys out there."
A torrential rain began in the third quarter, causing a sloppy game to become even messier.
Carolina's lone touchdown came when C.J. Wilson took a fumble by fourth-string running back Jalen Parmele into the end zone from 31 yards. John Kasay missed the extra point, leaving Carolina down 10-9.
In an effort to bolster a passing game that last season relied too heavily on dumpoffs to Pro Bowl running back Ray Rice, the Ravens added wide receivers Anquan Boldin and Donte' Stallworth. They also spread out the alignment to take advantage of Flacco's skilled right arm.
Baltimore amassed 196 yards in offense in the first half, only 22 of them on the ground. Rice started but did not touch the ball.
"The offense looked pretty good," said running back Willis McGahee, who had four catches during the 96-yard drive. "I think we're where we want to be at this point in time, but we still have a lot of work to do. We need to do a better job blocking for the quarterback; still, we're all happy that we kept moving the ball down the field."
After a sack by safety Tom Zbikowski ended Carolina's opening series, Flacco completed a 23-yard pass to Derrick Mason on Baltimore's first play from scrimmage. The third-year quarterback then hit Clayton for 18 yards on third-and-10 to set up a 32-yard field goal by free agent pickup Shayne Graham.
Late in the first quarter, after a punt pinned the Ravens on their 4, Flacco went 6 for 6 for 79 yards in a 10-play drive that put Baltimore ahead 10-0. His initial completion of the drive was a 12-yarder to Boldin, and Clayton's reception in the end zone took place in front of Captain Munnerlyn.
"Mark was one-on-one on the edge," Flacco said. "I just had to give time to get on top of the guy, and he made an unbelievable play."
There was speculation Clayton's playing time this season would be squeezed by Boldin, Stallworth and Mason, but Clayton finished with a team-high 48 yards receiving.
"Mark played tonight like he has all camp, and he's had a good camp," Ravens offensive coordinator Cam Cameron said.
Stallworth and Boldin had one catch.
Josh McCown exited Monday night's loss with a collarbone injury in the fourth quarter and left the locker room with his right arm in a sling. He had X-rays and is set for more tests Tuesday.
Ravens DE Brent Urban gets Jamison Hensley's game ball for blocking a field goal attempt that was returned for the game-winning touchdown while Pat McManamon gives his game ball to Browns QB Austin Davis for his performance in the fourth quarter.
Brent Urban blocks the Browns' game-winning field goal attempt and Will Hill returns it 64 yards for a touchdown as the Ravens prevail for a 33-27 victory.
On Monday, the Ravens get two touchdowns from special teams, including a blocked field goal returned for a touchdown as time expires.
Louis Riddick joins Scott Van Pelt and breaks down the play of the Broncos' offensive line and the state of the Seahawks' defense.
Steve Levy, Steve Young, Trent Dilfer and Ray Lewis evaluate the trending Redskins as they take on the Cowboys on Monday Night Football.