The Ravens' season on the brink was saved as much by whim as will.

Salvaging their playoff hopes along with sidestepping embarrassment, the Ravens found fortune in the fourth quarter to upend the bumbling Cincinnati Bengals, 27-23, before the smallest crowd ever at chilly Paul Brown Stadium yesterday.Surviving three quarters of misery and mistakes, the Ravens rallied from nine points down in the final period on the wings of Ron Johnson's fateful 22-yard return of a blocked punt, Todd Heap's improvised 22-yard touchdown catch and their defense's timely red-zone stand.

"Our offense, defense and special teams across the board took the challenge when it was issued," Ravens coach Brian Billick said.

The Ravens' first fourth-quarter comeback of the season evened their record at 6-6 and elevated them into a second-place tie with the Cleveland Browns in the AFC North.

Still 1 1/2 games back of the division-leading Pittsburgh Steelers, the Ravens remain playoff contenders in a season in which a salary cap purge and the loss of All-Pro linebacker Ray Lewis deemed them pretenders.

"It's unbelievable," Heap said. "From what we've been through this season, to get back to .500 and have the opportunity to improve on that in the last four games, that's huge. And we're supposed to be in a rebuilding year."

The Ravens entered the fourth quarter trailing 23-14, with no pizzazz in their passing game and little punch on defense.

But on the first play of the final period, opportunistic Ravens rookie Chad Williams, who already had run back an interception for a touchdown, came off the right edge untouched to block a Bengals punt deep in Cincinnati territory. The Ravens' Johnson, whose concentration has come into question with recent dropped passes, held his breath as the ball took a risky bounce and landed right in his hands.

Johnson ran 22 yards into the end zone to close the deficit to 23-21 nine seconds into the fourth quarter.

"I knew the ball was going to bounce, and it could have gone anywhere," Johnson said. "But it went straight up and came right to me. That was the luckiest bounce ever."

Owners of the NFL's worst record, the Bengals (1-11) created a stir from their announced crowd of 44,878 when they responded to that miscue by marching to the Ravens' 26-yard line. Cincinnati quarterback Jon Kitna, though, continued a quarter of self-destruction and bumped into running back Corey Dillon on a drop-back and fumbled.

The Ravens, who had one touchdown in their past 30 possessions, took their first lead of the second half on a methodical, 69-yard drive capped by a slow-developing pass play. On the series' 11th play, quarterback Jeff Blake eluded the pass rush and hit Heap in the end zone for a 22-yard, impromptu touchdown pass.

"That was going to be a defining drive for them," Billick said. "What they did was just outstanding."

The score took about seven seconds to develop as Heap had time to argue with an official about being held before realizing the play wasn't over. Seeing Blake scramble, Heap quickly became a wide-open target by crossing from the right side of the end zone to the left.

Heap's first touchdown in six games lifted the Ravens to a 27-23 advantage with 5:12 left in the game.

"You could have drawn it up in the sand and run it," Heap said.

The Ravens' only touchdowns came through the air, but most of their production came on the ground.

Despite an early 13-0 deficit, the Ravens never wavered from their commitment to the run. The Ravens called 31 running plays and 22 passing ones. Ravens running back Jamal Lewis recorded his fourth straight 100-yard game against the Bengals, rambling for 121 yards at a 5.5-yard clip.

Blake, however, came up big when it counted with scoring throws of 39 yards to Travis Taylor and 22 yards to Heap. But take away those passes and Blake was 8-for-17 for 54 yards.

"When you win, there's no frustration," said Blake, a former Bengal who won in his first game back in Cincinnati.

Like Blake, the Ravens' defense stepped up at the most opportune times.

Down 13-7 in the final seconds of the first half, Williams intercepted a pass from Kitna at the Ravens' 2, broke Kitna's tackle and ran down the right sideline for a touchdown. His 98-yard interception return tied a franchise record.

"I didn't know how far 98 yards was," Williams said.

Allowing the Bengals' offense to run up and down the field all game, the Ravens buckled down at the end. After the Ravens took a 27-23 lead in the fourth quarter, the Bengals converted three fourth-down plays and got to the Ravens' 13-yard line. It was there where Kitna completed a 3-yard pass and had three others knocked away.

Ravens defensive end Adalius Thomas batted down the final pass with 28 seconds left, deflecting it at the 5-yard line with his right hand that was fitted for a brace after he suffered a wrist injury earlier in the game.

Of the Ravens' six wins this season, their defense has now needed to stop a potential game-winning, fourth-quarter drive in four of them.

"I think we've been here a lot of times this year and we know how to respond," Thomas said. "It's just like another test. That's the only thing we count on was someone making a play."

For the first three quarters, the Ravens seemed to be giving the game away.

John Jones' holding penalty negated a 39-yard field goal in the first quarter. Then, a personal foul on Peter Boulware and an illegal leaping penalty on Randy Hymes set up the Bengals' 40-yard field goal that put Cincinnati ahead 16-14 with no time left on the clock in the first half.

The Ravens finished with eight penalties for 79 yards, and Billick expressed concern over the mental mistakes.

"We did a couple of dumb things today that should have cost us the game," Billick said.

The Ravens, who were 0-6 when trailing in the fourth quarter this season, finally had an answer this time and find themselves facing a bigger question.

"We're now at a point where, OK, where are going with this thing?" Billick said of his Ravens, who are at .500 for the third time this season but have never had a winning record. "We've got four games left, we're at .500 and that's a good sign. We are active and alive. We'll see how this thing plays out."