The kick after the touchdown was blocked -- punter Kyle Larson was temporarily replacing injured kicker Shayne Graham -- giving Cincinnati a 6-0 lead with 8:21 left in the first quarter.
Three plays after the score, Ravens rookie fullback Le'Ron McClain fumbled while trying to fight for more yards after his first career catch. The third turnover of the first quarter was converted into a 23-yard field goal by Graham, increasing the Bengals' lead to 9-0.
After the teams traded field goals, the Ravens were relieved to head into halftime with a 12-10 deficit.
"To only be down two at the half was amazing," Billick said.
But the Ravens' first series of the second half ended with another McNair fumble.
On the Ravens' third offense play of the third quarter, McNair's throwing arm was hit by end Geathers (who beat rookie right tackle Marshal Yanda) and the ball fell into the hands of linebacker Landon Johnson. He returned McNair's fumble 34 yards for a touchdown, extending Cincinnati's margin to 19-10.
The Ravens then staged an improbable comeback with a 23-yard field goal by Matt Stover and an impromptu return by Ed Reed.
Replacing injured punt returner B.J. Sams (who has a significant knee injury), Reed ran 63 yards untouched for a touchdown. Matt Stover's ensuing extra-point kick gave the Ravens their first lead at 20-19 with 12:07 left in the fourth quarter.
On third-and-one from the Ravens' 35-yard line on their next possession, the Ravens chose to throw instead of run the ball and paid the consequences. An overthrown McNair pass went off the outstretched hands of Derrick Mason and in the arms of a diving Geathers, who returned it 30 yards.
Two plays later, Palmer threw a 7-yard touchdown to T.J. Houshmandzadeh. Rudi Johnson ran in the two-point conversion, putting the Bengals back ahead, 27-20, with 8:48 remaining in the game.
Asked why he didn't run the ball on that third down, Billick said, "You anticipate what they're doing and you make the call that makes the best chance of succeeding."
McNair couldn't answer on the next drive, wildly overthrowing Demetrius Williams on third-and-six. It was McNair's last throw because he left with a groin injury.
After Reed recovered a Rudi Johnson fumble at the Bengals' 24, Kyle Boller came in and completed a 14-yard pass to Mason to convert a fourth-and-three.
The Ravens then ran eight plays inside the Bengals' 11-yard line, including six from the 3-yard line or closer. But they couldn't crack the end zone.
The Ravens will address Heap's disputed pass interference penalty with the NFL.
"We'll make the appropriate comments and turn them into the appropriate people and move on to the next game," Billick said.
Lewis, who was injured on his second play but returned to finish the game, and Sams are scheduled to have MRIs today.
McNair, who was injured on the game's first series, and Ogden will be evaluated throughout the week.
And backup tight end Daniel Wilcox has a bad ankle sprain and walked out of the locker room on crutches.
"Our players were dropping right and left, and I am proud of what this team did," Billick said. "To bring that up after a loss sounds a little feeble, but this team will stand together that way. The way we fought through this loss will pay dividends later."
Bengals 27, Ravens 20