SANTA CLARA, Calif. - The Bengals defense responded to AJ McCarron's first NFL start with a swarming effort that was the centerpiece of a 24-14 victory over the 49ers at Levi's Stadium that put them in the postseason for the fifth straight year.

The Bengals continue to stalk their second AFC North title in three years. They didn't get it Sunday when Pittsburgh beat Denver. But the 11-3 Bengals can win the divsion as well as the No. 2 seed with a win in Denver next Monday night.

Sunday's win was courtesy of a big-time defensive effort and stalwart 51.6-yard punting by Kevin Huber. The 49ers didn't convert a third down until their 13th try with less than three minutes left in the game and that set up wide receiver Anquan Boldin's 15-yard touchdown catch that cut the lead to 24-14 with 2:17 left in the game.

And they only got that one when what could have been cornerback Adam Jones' second interception of the game bounced crazily into the hands of wide receiver Torrey Smith.  The defense forced four turnovers and sacked 49ers quarterback Blaine Gabbert four times. They held Gabbert to a 58.3 rating and he completed 30 of 50 passes for 295 yards, less than six yards per throw.

McCarron didn't get much help from his running game against a San Francisco defense ranked next-to-last against the run and an offense that could manage only a field goal in the second half, when they got outscored, 14-3. As the game wound down, they finished with just 68 yards rushing on 36 carries.

 But playing with his well advertised calm McCarron delivered. He finished off some great field position with enough efficiency to get his first NFL win and the Bengals' first win in San Francisco since 1974. He hit 15 of 21 passes for 192 yards and a passer rating of 115.6

After throwing just 12 passes in the first while building a 21-0 half-time lead, the Bengals opened it up a bit on the first drive of the second half. McCarron made a great throw on third-and-13 when he threw a 16-yard rope to the sideline to wide receiver Marvin Jones for the first conversion of a third down longer than 10 yards against the 49ers all year.

McCarron then floated a perfect bomb to Jones in stride beating cornerback Kenneth Acker down the left sideline for 47 yards to the Niners 12.

But they couldn't punch it in and Mike Nugent hit a 22-yard field goal to make it 24-0 with 8:45 left in the third quarter.

On third-and-four from the 4, McCarron tried to hit wide receiver A.J. Green running across the end zone to the left sideline, but McCarron led him too far. That looked to be the last snap Green took.

At Saturday's practice at San Jose State, Green crashed into a retaining wall near the end of practice,  jostled his back and was made questionable moments before kickoff.

But Green started, had one catch for 37 yards, and when he was taken out it wasn't because of his injury.

The Niners made it interesting when they wrestled away an on-side kick away from wide receiver Mohamed Sanu and Gabbert immediately hit a 28-yard pass. But with 1:53 left, Bengals safety Shawn Williams outfought old friend Jerome Simpson for an interception at the Bengals 1.   

The Bengals were pitching a 24-0 shutout midway through the third quarter, but running back Jeremy Hill gave them the ball at the Cincinnati 46 when he fumbled the ball on a play right tackle Andre Smith got backed into Hill.

At that point the 49ers had the ball for 10 series and their longest drive had been 18 yards.

Gabbert hit Boldin on the sideline for a 29-yard gain to set up Bruce Miller's one-yard touchdown run that made it 24-7 with 3:14 left in the third.

it took one of those jaw-dropping highlight-film plays from left end Carlos Dunlap to ignite the Bengals in Sunday's grinding first half dominated by the Cincinnati defense with three turnovers good enough for a 21-0 half-time lead built in the final 5:16.

In the first game the 49ers allowed more than 20 points at Levi's Stadium this season, the Bengals' scores were set up Dunlap's forced fumble and 21-yard return, a shanked 18-yard-punt, and WILL linebacker Vontaze Burfict's interception off a great reaction on tight end Vance McDonald's bobble.

With the Bengals suffocating the Niners on all seven third-down tries in the half, they scored on drives of 11, 36 and 20. In an effort to protect McCarron, the Bengals threw it just 12 times in the half, but he made two big ones and went into halftime with eight of 12 passing for 102 yards with one touchdown pass for a 123.8 rating.

With the Bengals leading, 7-0, and facing a third-and-one from the Niners 8, McCarron hit wide receiver Marvin Jones wide open in a zone and that set up running back Jeremy Hill's second touchdown run of the game on a big one-yard push by the Bengals left side of the line to make it 14-0 with 1:17 left in the half.

Then Burfict, who also had one of the two sacks against Gabbert in the half, made his pick on the sideline and ran it to the Niners 20. On the first play McCarron hit wide open rookie tight end Tyler Kroft for his first NFL touchdown catch when he split the safeties on a blitz to make it 21-0 with 53 seconds left in the half.

In denying the 49ers on third down for the sixth straight time to open the game, Dunlap, after rushing the passer, dropped back to tackle Boldin after a completed pass. Dunlap ripped the ball out of Boldin's hands and returned it 19 yards to put it on the San Francisco 11.

In an effort to protect McCarron in his first NFL start, the Bengals had opted to throw it just eight times to that point and with help from a neutral zone penalty they ran it all five times on this drive. And that included Hill diving just short of the pylon to convert a third-and-two from the 3.

Hill didn't start for the first time all year and didn't appear until the second quarter. But he got a workout here. It took two more shots and on Hill's fourth try up close, the one-yard run that did end up as the score needed to be overturned when Bengals head coach Marvin Lewis challenged the spot.  It broke open a 0-0 game with 5:16 left in the half.   

Wide receiver A.J. Green, who was downgraded to questionable moments before the kickoff with a back injury, started and on the second drive of the game he caught a nice go ball from McCarron down the left sideline for 37 yards but that proved to be their only first down of the first quarter.

That put the ball on the 49ers 36, but the drive stalled on third-and-one and fourth-and-one when two Giovani Bernard runs got stoned. On fourth-and-one, running out of the I behind fullback Ryan Hewitt, Bernard went backward with NaVorro Bowman shooting the gap.

The Bengals couldn't mount a running game against the NFL's No. 31 defense, amassing just 22 yards on their first 10 carries and finished the half with just 36 yards on 19 carries.

 And they tried. On the next drive, Bernard got two yards each on the first two snaps and on third-and-six the Niners blitzed linebacker Eli Harold and he drilled McCarron as he threw it for an incompletion.

With the Niners crowding the line of scrimmage and daring McCarron to throw, the Bengals couldn't get any favorable third-downs. Backed up on his 11 on third-and-long, McCarron tried to hit Kroft over the middle, but in the face of pressure Harold dropped and tipped it high in the air and Kroft leaped to catch it far short of the third down.

The Bengals did get good field position early in the second quarter on Adam Jones' third interception of the season when he caught a carom off the hands of McDonald when McDonald took a shot from safety Reggie Nelson.

That put the ball on the Cincinnati 42, but even though they got a first down (on McCarron's naked nine-yard bootleg pass), they couldn't get another one. On third-and-eight McCarron and Green couldn't hook up over the middle to extend their third-down futility to 0-for-5.

But the Niners, their offense hounded by most of their six penalties for 48 yards in the half, whiffed on their first seven downs as they held  Gabbert to check-downs. He hit 11 of 17 passes for just 75 yards and the two picks as the day belonged to a Bengals defense that allowed just 105 yards in the half.

The Bengals were playing in the 49ers' new Stadium, but it was mausoleum of bad memories when the hosts rolled out a half-time reunion of the 1981 and 1988 champs that beat the Bengals in both Super Bowls.

ZAMPESE TALKS MAC: After practice one day last week, Bengals quarterbacks coach Ken Zampese talked about what he saw from AJ McCarron when he visited him at the University of Alabama leading up to 2014 draft, as well as his expectations in McCarron developing timing with his receivers.

In more buildings than most, Bengals position coaches are involved in the draft process and the campus visit is a big part of it. It is certainly not the determining factor, but the coach's observations are all part of the equation and Zampese had an interesting visit to Tuscaloosa.

He had heard about McCarron's intangibles and those thoughts were confirmed as he stood in a hallway with him in one vignette.

"He knew everybody. He had a word for everybody," Zampese said. "From the highest to the lowest, he had a relationship with everybody who walked past. He knew them all by name, he'd have a chuckle or a comment. Those things tell you the guy's invested in every level of the building. It says something about a guy and it's very positive."

Developing chemistry with McCarron and his receivers is an issue, but Zampese isn't overly concerned. McCarron hasn't thrown to them every day, but he's thrown to them enough.

"You need time on task, but that time on task is shorter with a guy like AJ who is instincts-oriented," Zampese said. "He's been around these guys. He hasn't thrown to them every single day, but he's thrown to them through time and he's watched them over time. He'll be fine."

And there was that perfect go ball to A.J. Green last week for a TD.

"I would imagine they've made that throw before some time down the line," Zampese said of this past season's spring workouts and training camp.

INACTIVES: McCarron's first NFL start contained no pre-game surprises when Bengals head coach Marvin Lewis delivered an inactive sheet that had quarterback Andy Dalton on it for the first time in his career.

Starting tight end Tyler Eifert (concussion) and starting strong safety George Iloka (groin) as well as backup rookie right tackle Jake Fisher (concussion) joined Dalton (thumb) on the list. They also opted to play Brandon Thompson at defensive tackle after Pat Sims played the last two games.

As they have been for much of the season or all of the season, rookie wide receiver Mario Alford and defensive tackle Marcus Hardison were inactive. With Eifert down, rookie Tyler Kroft got his fourth start and rookie C.J. Uzomah played in his third game. Both Margus Hunt and Will Clarke were active at defensive end.