The win, which put the Niners in position to secure the NFC's No. 2 seed, featured a number of impressive performances from both sides of the ball.
There was a lot to like, which is why a lot of high grades will be handed out.
Here is the 49ers' Week 15 report card.
Alex Smith wasn't flashy, but he was effective, throwing for 187 yards and a touchdown.
Most importantly, he was able to avoid getting sacked or intercepted.
All in all, Smith turned in a perfect game-manager performance.
He does lose points for a couple of missed throws, however.
Frank Gore didn't have a banner day, but he certainly got the job done.
Gore collected 65 yards on 18 carries in a performance that was highlighted by a game-sealing touchdown in the fourth quarter.
He has now amassed more than 1,100 yards in 2011.
Rookie Bruce Miller continued a surprisingly good season against the Steelers.
As of today, he is second in NFC Pro Bowl voting for fullbacks.
In addition to his excellent blocking, he was given a rare carry in Week 15.
Vernon Davis had perhaps his best performance of 2011 against the Steelers.
In the third quarter, he took an Alex Smith pass 31 yards to the 1-yard line.
Then, for good measure, he caught the one-yard touchdown pass.
In all, he totaled six catches and 72 yards.
Michael Crabtree was solid if unspectacular, notching four catches for 35 yards.
Crabtree didn't stand out too much, but he was generally competent.
Kyle Williams' numbers, four catches and 33 yards, are very similar to Crabtree's.
Williams' grade is better, however, if only for the fact that he has emerged quite nicely in recent weeks.
The second-year man has been a valuable asset for the depleted receiver corps.
Pass protection was phenomenal, as they allowed absolutely zero sacks.
The O-line has improved dramatically since the Thanksgiving debacle against the Ravens.
The offensive line also had a decent time as far as the ground game is concerned, paving the way for 100 rushing yards.
Joe Staley's second-half injury was the only down note.
Smith was able to disrupt Ben Roethlisberger for the whole game.
He also pounced on a crucial fumble to break the game open.
As an added bonus, he recorded three tackles.
Sopoaga has a nice game up front.
He managed to have two tackles when all was said and done.
McDonald also recorded a pair of tackles. He also registered half of a sack, bringing him to 4.5 on the season.
Smith was probably the MVP in Week 15's win.
He swarmed Big Ben all game, leading to 2.5 sacks.
The rookie sensation now has 13 sacks on the season, enough for a 49ers rookie record.
The 49ers' leading tackler lived up to his billing, recording eight tackles. Two of them were for losses.
Grant did a fantastic job subbing for an injured Patrick Willis once again. He had five tackles and, incredibly, four pass deflections.
Brooks didn't shine quite as much as his fellow linebackers. That's not to say he wasn't great in his own right, as he has a season-high six tackles.
Rogers continued his fantastic season Monday.
He notched his sixth interception of the season, in addition to two pass deflections.
The first-quarter interception set the tone for the defensive domination.
Brown had some problems early cover Mike Wallace, but hes responded beautifully. He ended up with two pass deflections and his third interception of the season.
The safety matched Rogers with his sixth interception of 2011. He also capped off an outstanding game with seven tackles.
Whitner stands out as the only starter in the secondary without a pick. But he contributed to the near shutout with a decent game.