San Francisco held onto its 1.5-game lead over Seattle in the NFC West with a 27-13 win against Miami.

It wasn’t exactly an awe-inspiring win -- the 49ers needed a 50-yard touchdown run from QB Colin Kaepernick to seal it late -- but the positives outweighed the negatives in what likely will be an important victory come season’s end.

Offense: B-

It was the type of offensive performance the 49ers were known for with QB Alex Smith under center -- solid, yet unspectacular. RB Frank Gore made the most of his 12 carries, running for 63 yards and a score, while RB LaMichael James made his NFL debut to keep the workhorse fresh. James’ had runs of 13 and 10 yards, as he finished with 30 yards on eight carries. Even Anthony Dixon got into the act with a pair of carries inside the 10, with the second a 1-yard touchdown run. Kaepernick was efficient as a passer, completing 18 of 23 passes for 185 yards without a touchdown or interception. San Francisco was held out of the end zone in the first half and its first touchdown was set up due to a fumbled punt inside the Miami 10. Its most impressive drive was a 13-play, 85-yard march to take 20-6 early in the fourth quarter. Previous game's grade: D

Defense: A

For the eighth time in 13 games this season, San Francisco limited its opponent to one or fewer touchdowns. Let that marinate. It’s at a point now where three-and-outs are expected and long drives by opponents indicate something’s gone terribly wrong. LB Aldon Smith’s two sacks of rookie QB Ryan Tannehill brought his NFL-leading total to 19.5 and within three of Michael Strahan’s NFL record set in 2001. With three games to play, it seems like a foregone conclusion that Smith will pass Strahan. Next up for Smith: Tom Brady on the road. Previous game's grade: A

Special teams: B+

New kicker watch will take a break this week after K David Akers was good on field goals from 30 and 37 yards. In addition to his debut as Gore’s backup, James returned three kickoffs for 79 yards with a long of 34 on the first touch of his career. C.J. Spillman recovered Dolphins PR Marcus Thigpen's muffed punt early in the second half. The special team's lone blemish was Thigpen's 56-yard kickoff return. Previous game's grade: C

Coaching: B+

There were some missed opportunities, but overall the 49ers played a solid game, executing the game plan. The coaching staff did a good job putting the players in position to take advantage of their strengths. The result was a 14-point win. Previous game's grade: C-

Follow 49ers reporter Kyle Bonagura on Twitter @CBS49ers and @KyleBonagura.