Painter threw three second-half touchdown passes to lead the Ravens to a 31-17 preseason win over the Falcons on Thursday night.
"I like the way our young guys competed and executed," said Baltimore coach John Harbaugh. "Curtis Painter made some big plays with three TD passes."
Painter started eight games for Indianapolis in 2011 before signing with the Ravens.
"Obviously, scoring three times while we were in there was a good thing," Painter said. "Just getting some momentum going. ... It was a good first showing. I've just got to keep going from here."
Ryan led two touchdown drives, including a scoring pass to Julio Jones.
Ryan completed 9 of 13 passes for 155 yards, one touchdown and one interception. He was 5 for 5 for 71 yards, including the 7-yard touchdown pass to Jones, on the opening drive for Atlanta.
"I thought the first couple of drives, especially the first drive, we got out to a good rhythm," Ryan said. "We were in the no-huddle in the first series, and it was good for us to work that package."
Jones had six catches for 109 yards and a touchdown.
Each starting quarterback left the game in the second quarter.
Ravens safety Omar Brown, an undrafted rookie from Marshall, had two fumble recoveries and an interception.
Ewing hurt his right knee when blocking on Dominique Franks' 45-yard punt return midway through the first quarter. Ewing, a fifth-round pick from Wisconsin, was helped off the field before being placed on a cart and driven to the locker room.
Dent walked off the field with the head injury he suffered when blocking on a Falcons punt. He is expected to take over at middle linebacker after Curtis Lofton signed with the Saints and Lofa Tatupu suffered a season-ending pectoral injury in training camp.
Baltimore backup defensive tackle Ryan McBean was carted off the field late in the first half with a left leg injury.
Painter, who played behind Flacco and Tyrod Taylor, completed 7 of 14 passes for 76 yards and the three touchdowns. Taylor completed 8 of 17 passes for 64 yards and had five carries for 51 yards.
The replacement officials included only two with Division I college football experience: referee Craig Ochoa and field judge John O'Brien. The other members of the crew have worked Division II, Division III and other professional leagues.
The crew seemed comfortable for the most part and even withstood the test of a replay when Falcons coach Mike Smith made an unsuccessful challenge on a sideline pass from Matt Ryan to Drew Davis. The officials ruled Davis was out of bounds and the call stood after review.
The officials referred to the Falcons as "Arizona" twice during the game, drawing chuckles from some fans.
The game matched two franchise quarterbacks from the 2008 NFL draft.
Flacco's 44 wins are the most by an NFL quarterback in his first four seasons. Ryan is second with 43 wins. Flacco has won at least one playoff game in each of his four seasons. Ryan has posted four straight winning seasons - a first for the Falcons - but has yet to win in the playoffs.
Ryan, operating in first-year offensive coordinator Dirk Koetter's attack, had completions of 13 yards to Roddy White, 26 yards to Jones, 19 yards to Jones and 6 yards to Jones on consecutive plays on Atlanta's opening drive.
After Michael Turner ran for 3 yards to the Ravens 7, Ryan went back to Jones for the touchdown pass.
The Falcons had a first down at Baltimore's 15 later in the first quarter when Ravens linebacker Brendon Ayanbadejo intercepted a pass from Ryan.
"That's just poor play in the red zone," Ryan said. "That's something I have to be better at, and I can't take points off the board."
Matt Bryant's 31-yard field goal gave Atlanta a 17-7 halftime lead.
"It was obvious in the first half that we have a lot of things to work on," Harbaugh said. "Really, we need to be better on offense, defense and special teams. There were times we played like the Ravens, but we were not consistent."
Justin Tucker kicked a 36-yard field goal for Baltimore in the third quarter.
A fumbled handoff by Atlanta third-string quarterback John Parker Wilson at the Falcons 10 was recovered by Baltimore's Brown midway in the third period. Three plays later, Painter threw a 4-yard pass to Billy Bajema for a 17-17 tie.
Painter's 22-yard pass to Deonte Thompson late in the third quarter gave Baltimore the lead.
Brown intercepted the first pass thrown by Atlanta fourth-stringer Davis to set up Painter's 18-yard TD pass to Bobby Rainey in the fourth quarter.
Brown recovered a fumble by Aron White following a catch later in the fourth quarter.
Atlanta backup Chris Redman couldn't move the offense as he completed only 1 of 6 passes for 8 yards. Wilson was 8 of 13 passing for 69 yards.