SAN FRANCISCO -- Send in the Seahawks? Yes, send in the Seahawks.

Once the 49ers defeated the St. Louis Rams 23-13 Sunday, their full attention shifted to Candlestick Park's next visitor: NFC West-leading Seattle.

The 49ers (8-4) are alone in second place behind the Seahawks, who will put their 10-1 record on the line Monday night when they host the New Orleans Saints (9-2).

"We feel we'll be ready for the test," safety Donte Whitner said, noting how the 49ers got "embarrassed" in a 29-3 loss at Seattle on Sept. 15.

Coach Jim Harbaugh said the 49ers, with a two-game win streak in tow, are well aware of the stakes and pressure they face next week, and each game thereafter.

"We control our own destiny," Harbaugh said, "and here we go."

Left tackle Joe Staley isn't going along for the immediate ride. He injured his right knee on Sunday's opening series and didn't return from what's initially diagnosed as a sprained medial collateral ligament, a league source confirmed.

Staley's injury soured the offense's proceedings, which included Michael Crabtree's 60-yard catch in his season debut, Anquan Boldin's team-high nine receptions for 98 yards and Vernon Davis' hurdling exhibition on a 17-yard touchdown catch.

If Staley is sidelined a few games, Alex Boone is poised to slide over from right guard and replace him, as was the case Sunday.

Boone's mindset heading into the rematch with Seattle: "It's another game to us. Anytime you overthink a game, you get beat. We'll go over details, but let's not make it more than it is."

The Seahawks certainly offer a stiffer challenge than the last-place Rams (5-7). The 49ers relied on a ball-control offense, a touchdown-preventing defense and heady special teams en route to 23-6 lead Sunday.

Although the Rams' Brian Quick had a last-minute touchdown catch, only three defensive starters were still in the game, allowing Whitner to note that the "starting defense" hasn't allowed a touchdown in its past 10 quarters.

"We wanted to stay in and not give up a touchdown, but we understand it's a bigger picture," Whitner said. "We've got Seattle coming in, there's playoff ramifications, and we didn't want to lose a guy in garbage time."

Sunday's victory was assured once Davis scored early in the fourth quarter, a play he finished by hurdling past cornerback Janoris Jenkins' right shoulder at the goal line. Davis used the same move to clear safety Rodney McLeod on a 20-yard, first-quarter reception.

Without Staley -- he's started every game since 2011 -- the 49ers seemed to follow up a couple positive plays with negative ones on each possession. As a result, they settled for Phil Dawson's three field goals and a Frank Gore touchdown run to build a 16-6 lead.

It wasn't until late in the third quarter that Crabtree emerged in 2012 form. He beat Trumaine Johnson's single coverage down the right sideline for a 60-yard reception to the Rams' 20-yard line.

That 60-yard catch matched a career high and it came on third down, where he often excelled last season. But the 49ers couldn't produce points off it as Gore lost a fumble two snaps later.

Crabtree's debut otherwise consisted of one other catch (for 8 yards) and two offensive penalties on the first series, and he often seemed like a mere decoy for Boldin and Davis.

The Rams sabotaged their comeback chances with a fake punt that Anthony Dixon and Michael Wilhoite suffocated, setting up Davis' touchdown catch on the next snap.

"It's the Rams, that's what they do," Dixon said of the Rams' special-teams chicanery. "We were just on alert. Everybody was on high alert."

Nobody on the 49ers needs a reminder of what the Seahawks have done to them the past two meetings. In addition to the Week 2 blowout, the 49ers got crushed 42-13 last Dec. 23 at Seattle.

"It's a different ballgame when we're up there in their arena," Whitner said. "When they come here, it's difficult for them."

The 49ers indeed have won the past four games against the Seahawks at Candlestick.

"They don't have the (CenturyLink Field) crowd noise to mess with our offense," Whitner continued. "On defense we feel we can match up with them. All we have to do is stop the run and not allow the quarterback to run around and beat us. That's why I feel like we can win."

For more on the 49ers, see Cam Inman's Hot Read blog at blogs.mercurynews.com/49ers. Follow him on Twitter at twitter.com/CamInman.

SUNDAY'S GAME
Seattle (x-x) at 49ers (x-x), 1:25 p.m. FOX

ONLINE EXTRAS
  • Scan this code with a smartphone to view a 49ers photo gallery or go to http://photos.mercurynews.com.
  • 49ers defense continues dominant run. Read story at mercurynews.com/49ers.
    SUNDAY'S GAME
    Seattle (10-1) at 49ers (8-4), 1:25 p.m. FOX

    INSIDE
  • Kawakami: Crabtree shines in return. PAGE 4
  • Knee injury expected to sideline Staley. PAGE 5