Bengals quarterback Joe Burrow started despite not being 100 percent because of his strained right calf.
He went 3-of-6 for 27 yards on the first drive, leading Cincinnati from its own 25 to the Los Angeles 37. Bengals kicker Evan McPherson missed a 56-yard field goal.
The Rams began their opening drive at their own 46 and needed only four plays to score what they thought was a touchdown. Tutu Atwell ran down the sideline for 24 yards to the end zone.
Replay reversed the ruling, with the replay official deciding Atwell stepped out at the 2-yard line.
DJ Reader sacked Matthew Stafford for a 9-yard loss on first down at the 2, and then Stafford threw two incompletions. Brett Maher made a 30-yard field goal and a 3-0 lead for the Bengals with 8:22 remaining in the first quarter.
