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SAN FRANCISCO -- Frank Gore purchased a gray hooded sweatshirt months ago specifically for this day, featuring an upside down teal dolphin in distress. Miami's mascot, on its head -- with a first-aid symbol and an "X" over each eye to boot.

"I said, 'We've got to turn him upside down,' " he said.

A Miami man through and through, Gore sure did his part.

Gore ran for a 1-yard touchdown and reached 1,000 yards rushing for the sixth time in his career, and even took the fake on Colin Kaepernick's late 50-yard scoring run in the San Francisco 49ers' 27-13 victory against the Dolphins on Sunday.

Gore, Kaepernick and Michael Crabtree pulled off just the kind of grind-it-out win coach Jim Harbaugh wants to see during the December stretch run.

Gore finished with 63 yards rushing, caught two passes and also matched his mentor, Roger Craig, and late Hall of Famer Joe Perry for the franchise record in rushing touchdowns with 50. And, no, Gore didn't grow up a Dolphins fan in his native South Florida.

"It's a blessing. Everybody says when you turn 29 and 30, you can't do it anymore. When I got to 29, I told myself, 'I'm going to overcome that,' " Gore said. "I've still got the explosiveness. When I see something, I go get it."

Anthony Dixon also had a 1-yard scoring run, while Kaepernick came through with the touchdown run and also passed for 185 yards in his fourth straight start since being promoted over Alex Smith.

Gore drew Miami's defense his way on that game-clinching play.

"Everybody came to me and Mr. Everything did his thing," Gore said of Kaepernick.

NFL sacks leader Aldon Smith added two more to his total for 19 1/2 , passing Fred Dean's franchise-best single-season mark of 17 1/2 set in 1983. Smith also moved within three sacks of Michael Strahan's seasonal NFL record set in 2001 with the New York Giants.

"Couple more, baby!" Gore hollered to Smith in the locker room.

Crabtree had nine catches for 93 yards and rookie LaMichael James ran for 30 yards in a solid NFL debut for the 49ers (9-3-1), who kept hold on the No. 2 seed in the NFC behind Atlanta.

Anthony Fasano made a diving 3-yard touchdown catch for Miami (5-8) midway through the fourth quarter on a pass from Ryan Tannehill. Fasano's right knee landed in the end zone as he fell out of bounds under pressure from safety Donte Whitner.

Miami went for it on fourth-and-10 from the 35 with 4:16 remaining, and Tannehill overthrew Marlon Moore on the left sideline.

"In the fourth quarter, we had some opportunities to put some more points on the board. We didn't. We were too generous," Dolphins coach Joe Philbin said. "It's just a lack of playmaking at critical times. That's it."

The sold-out crowd at Candlestick Park was treated to a spectacular, clear Bay Area day. The football didn't quite live up to it until both teams performed down the stretch.

Harbaugh's NFC West-leading Niners hardly looked like a power for most of the afternoon against overmatched Miami -- the team Harbaugh considered coaching before accepting a $25 million, five-year contract with San Francisco in January 2011.

"These games are really hard," Harbaugh said. "You've got to stay patient. We also took our shots."

The 49ers took advantage of a special teams blunder to end a stretch of five quarters and an overtime without a touchdown. Marcus Thigpen fumbled trying to catch Andy Lee's punt early in the third quarter, and C.J. Spillman recovered on the Dolphins 9 to set up Gore's short TD burst.

Cameron Wake had three first-half sacks to highlight a lackluster day by the Dolphins. On offense, Tannehill faced constant pressure.

Dan Carpenter kicked a 53-yard field goal in the third quarter for the Dolphins and also an earlier 28-yarder. Miami was held to 227 total yards.

"We just have to finish," Miami defensive tackle Paul Soliai said. "We just can't let this happen."

San Francisco went on fourth-and-1 on the 38 late in the third quarter and cornerback Sean Smith was called for pass interference against Crabtree. Dixon scored his second touchdown of the season five plays later.

Harbaugh stuck with Kaepernick a week after a 16-13 overtime loss at St. Louis, and the second-year pro delivered with an 18-for-23 day and 100.2 passer rating.

David Akers' 30-yard field goal in the second quarter tied the game at 3, then he kicked a 37-yarder as time expired before halftime to put his team ahead 6-3.

San Francisco lost defensive lineman and special teams standout Demarcus Dobbs to a right knee injury in the first half. He was carted off the field. Dobbs returned to the field after missing the trip to St. Louis a week earlier following his arrest on suspicion of driving under the influence and marijuana possession.

Aldon Smith lined up against rookie left tackle Jonathan Martin, a former Stanford star recruited by Harbaugh. Martin shifted to the left side in place of the injured Jake Long, placed on season-ending injured reserve Tuesday with an injured left triceps. Smith and Martin shoved each other all day, jawed and even butted helmets.

"This game's about power -- speed and power," Smith said. "I try to mix it up."

Game notes

Miami LB Koa Misi went down early in the third quarter with an ankle injury. ... The 49ers won nine games in back-to-back seasons for the first time since 2001-02. ... Under Harbaugh, the 49ers improved to 3-0 against the AFC East and 6-1 vs. the AFC. ... 49ers LB Tavares Gooden sustained a rib injury.

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