SAN FRANCISCO — Coach Mike Singletary delivered another one of his motivational halftime speeches and the San Francisco 49ers woke up in a hurry.

And in all phases, no less.

"It was just a matter of reminding them what was at stake," Singletary said.

Like first place in the NFC West.

Tight end Vernon Davis caught a 13-yard pass for his third touchdown in two weeks, Patrick Willis returned an interception 23 yards for a score and the 49ers overcame the absence of star running back Frank Gore with a 35-0 rout of the winless St. Louis Rams yesterday.

The 49ers (3-1) took command of the NFC West with their first shutout in 119 games since a 38-0 win at New Orleans on Jan. 6, 2002.

"Any day you look up and see a goose egg it's great," Willis said. "We made a step today. People are going to say it's only St. Louis. That doesn't matter."

The Rams (0-4) lost their 14th straight, the longest skid in the NFL.

San Francisco scored touchdowns via special teams, offense and defense for the first time since Nov. 10, 1997, in a 24-12 win at Philadelphia. This also marked the 49ers' largest margin of victory since a 50-14 win over Arizona on Dec. 7, 2003.

"This is our house," said Singletary, sharing his halftime message. "We want to set the tempo. We don't want any team coming in here and setting the tempo. I felt like they were taking a fight to us."

Josh Morgan caught a 24-yard touchdown pass from Shaun Hill early in the fourth quarter, then Ray McDonald scooped up a fumble by Rams quarterback Kyle Boller and ran 11 yards for another TD 14 seconds later.

San Francisco found a fortunate, wacky way to finally get on the board late in the first half. Rookie fifth-round draft pick Scott McKillop recovered a botched punt return by St. Louis in the end zone. And a lackluster first half by the Niners' offense turned lively in the last 30 minutes.

"That's huge that every unit is pitching in," Hill said. "We're on top of the division. That's right where we need to be at the quarter mark."

McKillop capitalized when St. Louis' Danny Amendola let Andy Lee's punt go and teammate Quincy Butler tried to pick up the ball but couldn't gain control. The 49ers swarmed and McKillop came up with the ball at the bottom of the pile.

Boller had a tough return to the Bay Area in his first start for St. Louis. A former college star at Cal , he went 13 for 24 for 108 yards and was sacked five times in place of injured starter Marc Bulger (bruised rotator cuff).

Willis wreaked havoc, often blitzing untouched to finish with eight tackles — five solo, three for loss — and 2 1/2 sacks to go with three other hits on Boller.

Without Gore, who injured his ankle at Minnesota in Week 3, the 49ers struggled to move in their power run offense. Rookie Glen Coffee took on a bigger role, but finished with 74 yards on 24 carries.