SAN FRANCISCO -- The San Francisco 49ers and St. Louis Rams played 75 minutes and decided nothing Sunday at Candlestick Park.
The Rams and 49ers settled for a 24-24 tie, failing to score in overtime despite having numerous good chances.
The 49ers lost quarterback Alex Smith to a concussion in the second quarter. Backup Colin Kaepernick took over with his team trailing 14-7. He completed 11 of 17 passes for 117 yards and ran eight times for 66 yards and a touchdown.
Rams quarterback Sam Bradford went 26-for-39 for 275 yards and two touchdowns. Wide receiver Danny Amendola, returning after missing three games with a shoulder injury, caught 11 passes for 102 yards.
The Rams got the ball first in overtime and looked like they were headed for a victory when Bradford hit Amendola for 80 yards on first down to the 49ers' 2. But an illegal formation penalty on offensive tackle Rodger Saffold killed the play, and the Rams wound up punting.
The 49ers quickly marched into field goal range, but the usually reliable David Akers pushed his 41-yarder wide left, and the Rams took over at their 31.
Bradford drove the Rams into 49ers territory, and Greg Zuerlein split the uprights on a 53-yard field goal attempt, but the Rams were flagged for delay of game. So Zuerlein tried again, this time from 58 yards, and pushed his attempt wide right.
The 49ers took over on their 48 with 2:48 left in overtime, but the Rams forced a punt. St. Louis got the ball back on its 14 with 1:36 left but got no farther than the 49 before time ran out.
Trailing 21-17 with just over five minutes left, the Rams faced fourth-and-eight from their 33 and sent in punter Johnny Hekker. Late in the first half, the Rams faked a punt, and Hekker threw a 21-yard pass from his end zone to Rodney McLeod. This time, Hekker threw a 19-yard pass to tight end Lance Kendricks, and the Rams kept marching for the go-ahead touchdown.
Bradford threw a two-yard touchdown pass to wide receiver Austin Pettis with 1:09 left to play.
The 49ers answered quickly, driving 63 yards for Akers' 33-yard field goal with three seconds left in regulation. Kaepernick did much of the work with his legs, running for 19 yards on first down then adding a 10-yard run.
Smith, who suffered a concussion last season against Dallas, left the game after leading the 49ers on a 12-play, 78-yard touchdown drive, spanning the first and second quarters. Early in the drive, Smith was forced to scramble and took a blow to the back of his helmet as he went down from Rams linebacker Jo-Lonn Dunbar. Three plays later, Rams defensive tackle Michael Brockers sacked him. He took more contact when he gained one yard on a fourth-and-one quarterback sneak.
Smith's 14-yard touchdown pass to Michael Crabtree cut the Rams' lead to 14-7 with 8:13 left in the first half. But after the 49ers' defense forced a punt, Kaepernick took over at quarterback with 6:31 remaining. Smith walked slowly to the locker room minutes later and was ruled out with a concussion before the first half ended.
Kaepernick, a second-round draft pick out of Nevada last year, had seen spot duty in five games before Sunday, completing 5 of 9 passes for 89 yards and rushing 13 times 111 yards and two scores. But in his first extended action of his career, Kaepernick stuggled early against the Rams' defense before heating up.
The Rams upped their lead to 17-7 with 18 seconds left in the third quarter on Zuerlein's 27-yard field goal. But with 8:40 left to play, Kaepernick capped an 81-yard drive with a seven-yard touchdown run, cutting the Rams' lead to 17-14. He went 5 of 5 for 67 yards on the drive, but also muffed a snap and fumbled after being sacked. Both times the 49ers recovered, and Frank Gore ran 12 yards after picking up the botched center-QB exchange.
The 49ers got the ball back on the ensuing kick when Tramaine Brock forced Rams return man Isaiah Pead to fumble, and Darcel McBath recovered at the St. Louis 20. One play later, Gore raced around right end for a 20-yard touchdown, putting the 49ers ahead 21-17 with 8:23 left.
The Rams had taken an early 7-0 lead on Bradford's 36-yard touchdown pass to rookie wide receiver Brian Quick. Cornerback Chris Culliver tried to bump Quick at the line, but Quick delivered a blow that sent Culliver to the turf. Bradford hit a wide open Quick along the right sideline, and he raced into the end zone, capping a 66-yard drive.
Steven Jackson ran for 23 tough yards on four carries during the Rams' first touchdown drive, and he put the Rams ahead 14-0 with a seven-yard scoring run with 1:47 left in the first quarter. The Rams marched 93 yards for that score, with Bradford completing 3 of 3 passes for 36 yards and Daryl Richardson gashing the 49ers on a 32-yard cutback run.
NOTES: The Rams played without two key rookies -- starting right cornerback Janoris Jenkins and wide receiver Chris Givens -- who were benched and inactive for violating team rules. Rookie Trumaine Johnson started for Jenkins and Amendola replaced Givens. .. Saffold played -- and started -- for the first time since Week 2 against Washington when he suffered a knee injury.