SAN FRANCISCO — When 49ers linebacker Takeo Spikes met Glen Coffee, he told the rookie how much he disliked him.

“Why?” Coffee said, stunned.
“Because you used to run all over Auburn,” Spikes replied.
Suffice to say, Spikes is glad to have Coffee on his side now. The third-round pick out of Alabama rampaged through the Raiders’ defense for 129 yards in a little more than one quarter of action during the 49ers’ 21-20 exhibition victory Saturday night at Candlestick Park.
Running back Frank Gore played only a series before enjoying Coffee’s spectacular 16-carry show.
“He’s doing a great job,” Gore said of his understudy. “Running strong. Finding the holes. Glen’s going to be a great player.”
Coffee was the runaway highlight for the 49ers in an otherwise mixed performance.
Neither Alex Smith (3-of-9, 30 yards) nor Shaun Hill (3-of-7, 20 yards) did enough to settle the quarterback debate. Coach Mike Singletary said afterward that he needed to review game film before giving his full evaluation. Singletary said he did not know if he would announce his regular-season starter before next week’s game in Dallas.
Based on the way the offense operated Saturday, the 49ers might just take the quarterback who hands the ball off best. Besides Coffee, fellow backs Michael Robinson (97 yards) and Kory Sheets (51 yards) helped the 49ers average 5.9 yards per rush.
Of the 10 longest 49ers plays, seven came on the ground.
“It was important for us to establish an aggressive approach to this game, to really establish the run,” center Eric Heitmann said. “I think we accomplished that today. I think it’s something we can build on.”
Coffee certainly played like a building block. Listed at 6-foot, 209 pounds, the 74th overall choice followed up his 67-yard effort of a week ago with a defender-dragging performance in the second quarter.
He dashed. He smashed. He gashed.
At one point, he ripped off consecutive runs of 18, 18 and 35 yards (over the span of two drives).
“The offensive line made it easy tonight,” Coffee said.
His most impressive run went for just 3 yards when he dragged 205-pound safety Tyvon Branch along with him in a goal-line situation.
Singletary, though impressed by the rookie, has no appetite for a running backs controversy. He said that Coffee is not necessarily earning a bigger share of the workload for 2009 and that the kid’s role remains the same — to give Gore a rest on occasion.
“Frank Gore is one of the top five backs in the league,” the coach said. “We’re going to give the ball to Frank.”
While the ground game was off and running, the rest of the 49ers’ night was a mixed bag.
The 49ers’ defense has just one sack over two games, and that was a fluke: Raiders quarterback JaMarcus Russell tripped over his own running back for a 9-yard loss.
The secondary, meanwhile, had to eat some humble pie a few days after some brash celebrations during a joint practice session against the Raiders in Napa. During that Wednesday practice, the 49ers intercepted four passes in a single red zone drill with Clements at one point yelling, “I love it when they can’t compete with us!” But the Raiders competed just fine Saturday.
With about 10 minutes to play in the second quarter, Raiders receiver Johnnie Lee Higgins had a step on Clements, who grabbed Higgins’ jersey in desperation. The 22-yard pass-interference call gave the Raiders a first down at the 49ers’ 13.
Minutes later, Louis Murphy — who did plenty of trash-talking on Wednesday — ran by Clements and safety Mark Roman was late providing help. The result was a 24-yard touchdown pass from Russell that gave the Raiders a 7-0 lead.
“We just did not execute the defense properly,” Singletary said.