In a matchup of teams that lost in the wild-card round of the playoffs last season, Cincinnati had the deeper roster.
The second- and third-string players for Atlanta struggled in the second half for the second straight week.
Ryan, who completed his first 11 attempts, finished 18 of 21 for 174 yards and one touchdown, a 2-yard screen to reserve fullback Lousaka Polite in the second quarter.
Spreading out the offense and connecting with nine different receivers, Ryan completed passes of at least 20 yards to Roddy White, Tony Gonzalez, Julio Jones and Michael Palmer.
Dalton was 8-of-14 for 125 yards and one TD, a 50-yard pass that star receiver A.J. Green caught while running past cornerback Asante Samuel down the right sideline.
The Bengals (2-0) are hoping that tight end Jermaine Gresham isn’t badly hurt after the 24-year-old Pro Bowl alternate limped off the field in the first quarter with a right knee injury. The team gave no immediate update to Gresham’s condition, other than to say he would not return to the game.
Cincinnati’s offense began the night with starting running back BenJarvus Green-Ellis out with a foot injury and his top backup, Bernard Scott, sidelined by a sore hand.
The Bengals lost starting left guard Travelle Wharton to a season-ending knee injury in last week’s preseason win over the New York Jets.
Atlanta’s Michael Turner had three carries for minus-3 yards. Turner’s best gain was an 8-yard completion on a screen pass.
Samuel, the veteran Atlanta acquired in an April trade with Philadelphia, seemed to celebrate prematurely after his coverage contributed to a short incompletion that Dalton threw too high for Green.
On the next snap, Green ran straight ahead on a “go” route and easily beat Samuel to make an over-the-shoulder catch that put the Bengals up 10-3.
Ryan answered with a nine-play, 88-yard drive that ended with a 2-yard TD catch by Polite. An over-the-middle pass on the previous snap to Jones, last year’s No. 6 overall draft pick, covered 23 yards.
The game was tied 10-all when Ryan and Dalton left the game late in the second quarter.
Chris Redman took over for Atlanta, directing a nine-play drive that ended with Matt Bryant’s 22-yard field goal and gave the Falcons a 13-10 halftime lead.
Bruce Gradkowski, the Bengals’ No. 2 quarterback, helped Cincinnati take a 17-13 lead early in the third on a 12-yard touchdown pass to rookie Mohamed Sanu.
Mike Nugent kicked a 54-yard field goal to give the Bengals a 3-0 lead on the fourth drive of the game. Bryant tied it at 3-all with a 20-yarder early in the second quarter.
Atlanta safeties Thomas DeCoud and William Moore combined to force and recover a fumble from running back Brian Leonard on Cincinnati’s first possession, but the Falcons followed with a three-and-out.
In the fourth quarter, Jourdan Brooks’ 1-yard touchdown run gave the Bengals a 24-13 lead. Atlanta (0-2) made it 24-19 late in the fourth when LaMark Brown caught a 7-yard TD pass from Dominique Davis. The Falcons’ 2-point conversion pass failed.