ATLANTA – The Bears’ inability to score in the red zone cost them dearly in Sunday night’s mistake-filled 21-14 loss to the Atlanta Falcons in the Georgia Dome.

At no time was that more evident than when running back Matt Forte fumbled on back-to-back plays from the Atlanta 1-yard line late in the third quarter with the Bears trailing 14-7.

Matt Forte fumbles while diving for the end zone in Sunday night's 21-14 loss to the Atlant Falcons.

On second-and-goal, Forte tried to leap for the goal line. But the ball squirted loose when he was hit by linebacker Curtis Lofton. While fortunate to recover his fumble at the 1, Forte wasn’t so lucky on third-and-goal as defensive tackle Jonathan Babineaux popped the ball free and linebacker Coy Wire smothered it at the 2.

“It’s very frustrating,” said Forte, who lost his first fumble of the season, matching his total from all of last year. “I can’t turn the ball over and I turned the ball over.”

Forte was limited to 23 yards on 15 carries by a Falcons run defense that ranked 24th in the NFL entering Sunday’s action.

“It’s like that sometimes,” said coach Lovie Smith. “They’re a good football team. They’re a 4-1 team. They have a decent defense. You’re not going to always be able to run the football against them. I thought we did some good things at times against them though.”

Not again: Starting for the first time since spraining his knee on the first defensive play of the season, strongside linebacker Pisa Tinoisamoa was carted to the locker room in the second half after injuring the same knee. He was replaced by Jamar Williams.

“Pisa went down with a knee injury; that’s about all we know,” Smith said. “He couldn’t finish the football game. Of course there’s concern when that happens.”

Johnny rocket: With a 23-yard touchdown reception on the first play of the second quarter, Johnny Knox became only the second Bears rookie to score TDs in four straight games since 1970. The fifth-round draft pick joins Hall of Fame running back Walter Payton, who accomplished the feat in 1975.

Prior to Sunday night, Knox caught 7-yard TD passes from Jay Cutler in back-to-back wins over the Steelers and Seahawks before returning a kickoff 102 yards for a score in a victory over the Lions.

Select company: With three catches for 32 yards, tight end Desmond Clark moved past wide receiver Harlon Hill into 10th place on the Bears’ all-time receptions list with 228.

The only players ahead of Clark are Walter Payton (492), Johnny Morris (356), Marty Booker (329), Curtis Conway (329), Mike Ditka (316), Neal Anderson (302), Matt Suhey (259), Bobby Engram (246) and Dick Gordon (238).

Shut out again: The Bears failed to sack Falcons quarterback Matt Ryan for the second straight game. They were also blanked in last season’s 22-20 loss in Atlanta.

On Sunday night, Ryan completed 19 of 33 passes for 185 yards with 2 touchdowns, 2 interceptions and a 68.4 passer rating. In last year’s contest, the young quarterback connected on 22 of 30 passes for 301 yards with 1 TD, no interceptions and a 116.1 passer rating.

The Bears entered Sunday night’s contest tied for fourth in the NFL with 14 sacks, which is exactly half their total from all of last season. Only the Vikings (18), Broncos (16) and Steelers (15) had more prior to Sunday. Adewale Ogunleye leads the Bears with 4½ sacks,  followed by Alex Brown with 2½.