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A second quicker on this play, another body on the line of scrimmage in that play, and the St. Louis Rams would have upset powerful San Francisco, a signature win in Year 1 of Jeff Fisher's rebuilding program.

Instead, earlier this month the teams played to the NFL's first tie in four seasons.

Think that didn't get the 49ers attention?

Three weeks later isn't soon enough for the class of the NFC West to get a do over.

"I would say everybody in the locker room is anxious to play these guys," 49ers safety Donte Whitner said of Sunday's rematch in St. Louis. "Last time they came in here, they were ready to play, they came out and punched us in the mouth a little bit, and by the time we woke up we found ourselves in a tie.

"This time we want to go into it ready from snap one, and see where things fall."

This time, they aim to show who's in charge.

"We have to do what we didn't do the first time we played them, and that's start fast," running back Frank Gore said. "We've got to go out there and try to start fast, and once we start fast we've got to keep our foot on the gas."

The notion that a 24-24 tie on Nov. 11 awoke a sleeping giant prompts a long pause from Fisher, who has already doubled the Rams' win total from last season. Fisher concedes nothing in his first season back in the NFL after a year's sabbatical.

"You can call it whatever you want. I wouldn't call it a wakeup call for them," Fisher said. "I'd call it a hard-fought physical game that neither team won, so ..."

The Rams (4-6-1) dominated the Niners (8-2-1) from a statistical standpoint, putting up 458 yards and going 9 for 18 on third- and fourth down conversions. But they missed out because of penalties that wiped out three golden opportunities.

Two of them nullified 142 yards in gains by Danny Amendola: a 62-yard punt return to the 49ers 2 in the third quarter that would have put the Rams on the doorstep of a 17-point cushion, and an 80-yard reception on the first snap of overtime — also to the 2. That was called back because they didn't have enough players on the line of scrimmage.

Rookie kicker Greg Zuerlein booted a potential winning 53-yard field goal in overtime, but just after the play clock elapsed because rookie holder Johnny Hekker lost track of time. Zuerlein couldn't convert on a 58-yard attempt, and the Rams got no more chances to squander.

So, of course the Rams think they can play with them.

"They're in our division and it once was a rivalry, so we just go back to that," cornerback Cortland Finnegan said. "You know what, I guess we've got to crank up our cars and put the gas pedal down.

"Let it be a game that people will remember."

So little time has passed, the rematch feels a bit like a continuation. Like it's still tied and waiting for somebody to make that keynote play.

49ers tight end Delanie Walker confessed he wasn't aware games could end in a tie.

"I don't know a lot of rules in the NFL," Walker said. "I know the basics. I just didn't know the rule at first. Now, I know."

For days after the first meeting, Rams defensive end Chris Long said it felt like a loss and he would have rather just keep playing.

"Absolutely," Long said. "I'm sure they feel the same way. It was a hard-fought game and now it's the tiebreaker. It'll be a heck of a game."

49ers coach Jim Harbaugh called it "an interesting way to look at it," before adding, "I think it's just new business. That game is finished business and this game coming up is new business."

Fisher expects a rematch that bears little resemblance to Game 1.

"Experience kind of suggests that when you play games three weeks or four weeks apart, the second game is usually completely different," Fisher said. "They don't mirror each other at all. We've got to take the same approach, the same physical approach, as they will into the game and then just make plays."

Both defenses set the tone last week.

Whitner and linebacker Ahmad Brooks each returned interceptions for touchdowns and the 49ers had five sacks in a 31-21 victory at New Orleans. That's come to be expected in San Francisco, with a unit ranked second overall in the NFL, fourth against the pass and second against the run.

If not for the tie, the 49ers would be on a five-game winning streak.

Janoris Jenkins became the first rookie since 1960 and first Rams player to return two interceptions for touchdown in a game as the Rams won 31-17 at Arizona. St. Louis totaled four interceptions, emphatically ending a five-game turnover drought that was tied for the NFL's longest since 1950.

Fisher jokingly credited backup quarterback Kellen Clemens for providing turnover opportunities in practice last week, and again the day after the Rams finally broke through, saying Clemens "threw about a dozen picks."

Of course, he's not satisfied, noting the Rams have recovered one fumble all year.

"We were fortunate to come up with the interceptions," Fisher said. "But we still need to get on balls and knock them loose."

Just like the last meeting, the Rams will try their best to rattle an unproven quarterback. They had little success in San Francisco with second-year pro Colin Kaepernick, who stepped in after Alex Smith was sidelined by a concussion and rallied the 49ers to force overtime.

Harbaugh's decision to stick with Kaepernick, 2-0 as the starter, over a healthy Smith came as no surprise to the Rams. Kaepernick was steady if well shy of spectacular last week, passing for 231 yards and a touchdown, and Harbaugh said it came down to a player who had the "hot hand."

"It feels good that coach has confidence in me going out there," Kaepernick said. "You have their scheme fresh in your mind, you get a little refresher, so things come back to you pretty quick."

The 49ers are 4-1 on the road this year and 10-3 in two seasons under Harbaugh, tied with the Texans for the NFL's best record over that span.

Another week, another dome.

"The Superdome is an extremely tough place to play. It's very loud," Whitner said. "It's going to help us this week."

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AP Sports Writer Janie McCauley in San Francisco contributed to this story.

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