Final Score: San Francisco 27, Arizona 6

Glendale, AZ (Sports Network) - Brian Westbrook had his first big game in a 49ers uniform, rushing for 136 yards and a touchdown in place of Frank Gore to lead San Francisco to a 27-6 win over Arizona on Monday night.

Thrust into a featured role when Gore went down with a fractured right hip, Westbrook carried the ball 23 times for more than double his touches in eight previous games for the 49ers.

"I kind of found my groove a little bit," said Westbrook.

San Francisco (4-7) also got 129 passing yards from Troy Smith, who connected with Michael Crabtree for a 38-yard touchdown in the first quarter that opened the scoring and gave the 49ers the lead for good.

The Cardinals (3-8) only managed two Jay Feely field goals and 203 total yards of offense in their sixth straight loss, dropping them two games back in an NFC West Division led by two 5-6 teams.

There was frustration on the Cardinals' side, especially from their quarterback.

Derek Anderson cursed several times and stormed out of the interview room after being asked about a clip during the TV broadcast that showed him laughing with one of his linemen on the sideline during the fourth quarter.

The Cardinals trailed by 18 points at the time.

Anderson, who passed for 196 yards and was intercepted once, said he didn't like getting embarrassed on national TV. Anderson and Beanie Wells fumbled the handoff on Arizona's first play of the game.

"I'm not laughing about it. You think this is funny. I take this [expletive] seriously," Anderson barked during the tirade. "I put my heart and soul into this every week."

"I don't want to go out there and get embarrassed on Monday Night Football in front of everyone," he said.

What's embarrassing? The two-time defending NFC West champions are on the cusp of their first losing season since 2006.

San Francisco, meanwhile, moved within a game of division-leading Seattle and St. Louis. The 49ers have won four of their last six games since beginning the season 0-5.

"The guys continue to work and continue to fight and it says a lot about who they are," said San Francisco head coach Mike Singletary.

Westbrook had only touched the ball 10 times -- five rushes and five passes -- since being signed by the 49ers after eight productive seasons in Philadelphia.

But the 31-year-old back was thrust into a load-bearing role Monday when Gore couldn't make it back on the field.

Gore went to the locker room after San Francisco's opening drive -- he had runs of 25 and 15 yards during it -- which ended in a missed 47-yard field goal by Shane Andrus.

He returned later in the quarter, but only took two more carries, including one that was negated by a penalty. He finished with five carries for 52 yards.

A report posted late on NFL.com said Gore's injury will sideline him for the rest of the season.

Smith hit a diving Crabtree in the end zone for a quick-strike touchdown on the first play after Anderson and Wells fumbled their handoff, giving the 49ers a 7-0 lead.

Arizona responded with a 31-yard field goal from Feely to get within 7-3, but the 49ers built a 14-3 lead by the end of the first quarter on Anthony Dixon's diving one-yard TD.

Westbrook could have had a TD on the drive, but he dove over the left pylon with the football in his outside hand.

No matter. Westbrook scored his first touchdown of the season on an eight-yard run midway through the second quarter to give the 49ers a 21-3 lead.

The Cardinals got a 39-yard field goal from Feely on the ensuing possession to pull within 21-6, but were unable to do anything after intercepting Smith three plays into the next drive.

After missing his first kick of the night and having one blocked by Dominique Rodgers-Cromartie, Andrus booted field goals of 38 and 26 yards in the second half to account for the final score.

Westbrook, who racked up nearly 10,000 rushing and receiving yards with the Eagles, said it felt good to show the young guys on the 49ers what he could do.

"Some of them have been able to see the things I've done over my career, some of them just don't know," he said. "So for me it meant a lot to go out there and play and to have the opportunity for some success."

Game Notes

Crabtree caught two passes for 48 yards...Smith was 11-of-23 passing...Takeo Spikes intercepted Anderson near the end of the third quarter and lateralled it to Nate Clements for a spectacular zig-zagging run, but Spikes was ruled down at the spot of the pick. Still, the 49ers turned it into one of Andrus' field goals.