"Frank Gore motored to his right before running into a road block.

He slammed on the brakes and took a detour to his left, leaving one Ravens defender in his dust before defensive end Cory Redding spun him down in the backfield for a one-yard loss.

That negative run was a microcosm of Thursday night for the San Francisco running back, his wheels spinning in place -- and the 49ers offense stuck in the mud -- in a Ravens' 16-6 win. Gore ran for 39 yards on 14 carries against a Baltimore defense playing without linebacker Ray Lewis (toe) for a second straight game. His backup, Dannell Ellerbe (thigh), was inactive, too.

Gore's backup, Kendall Hunter, had four carries for 14 yards as the 49ers, who entered Week 12 with the NFL's sixth-ranked running attack, finished with 74 rushing yards on 21 carries.

"I don't think you could have stopped the run any better," Ravens coach John Harbaugh said.

San Francisco's game plan was clear heading into the Harbaugh Bowl. The 49ers rolled into M&T Bank Stadium with a 9-1 record thanks in large part to the damage Gore has done running behind his beefy offensive line. With Gore averaging 4.6 yards per carry entering the game, the 49ers had hogged the ball this season, making things easier for quarterback Alex Smith and keeping the 49ers defense fresh.

But on Thursday, the Ravens got excellent penetration up front and stuffed Gore when he ran up the middle. When he bounced it outside, he didn't find much running room there, either."