The San Francisco 49ers just beat the Los Angeles Chargers 41-17. Here are the 49ers' grades for this performance.

QUARTERBACKS: A-MINUS

Brock Purdy played one drive and completed 4 of 6 pass attempts for 29 yards. He moved the chains twice on third down with a pair of seven-yard completions to De'Zhaun Stribling (more on him in a minute). Purdy even scrambled for three yards to set up third and manageable. Overall, he was solid without his veteran playmakers. The next quarterback, Mac Jones, made two of the best throws of the night -- a 21-yard dime over the middle to Stribling, and a deep strike to Stribling who dropped the ball. Jones has a beautiful deep ball, which makes him a great fit with Stribling and Mike Evans. I still would like to see Purdy hit those two down the field. The third quarterback, Adrian Martinez, threw a pick-six, a second interception, he ran for a touchdown and threw a touchdown pass to Jordan Watkins. He seems like a fine scout-team quarterback who shouldn't ever ever ever play meaningful snaps.

RUNNING BACKS: B-PLUS

Kaelon Black showed that he's explosive and tough even though he averaged just 4.1 yards per carry. He looks like he will improve the running game, even if its biggest issue is still the blocking, particularly along the interior of the offensive line. The longest run of the night belonged to Sincere McCormick, who gained 37 yards up the right sideline. He's having a good training camp and just might make the team over Isaac Guerendo, who has been injured all offseason.

WIDE RECEIVERS: B-PLUS

De'Zhaun Stribling was excellent despite dropping a perfectly placed deep throw from Mac Jones and whiffing on a run block for the second time in two preseason games. He still has so much room for improvement, and yet he already is the second-best wide receiver on the team behind Mike Evans. Which means when Evans is injured, which is often, Stribling is the No. 1 receiver on the team. The second-best wide receiver tonight was Jordan Watkins, who caught a long pass in the first half and a touchdown pass in the fourth quarter. Too bad he'll have to sit behind washed-up veterans such as Deebo Samuel and Demarcus Robinson all year. Speaking of those two, they played and did next to nothing. Samuel had two targets for one catch and four yards. Yippee. Thank goodness they have Stribling.

TIGHT ENDS: C

Luke Farrell may know the offense better than last year, but he still seems pretty mid to me. Good thing they have Jake Tonges and George Kittle, who might return for the season opener against the Rams.

OFFENSIVE LINEMEN: C-PLUS

Carver Willis started at left guard and actually created some movement at the point of attack, which allowed the 49ers to run the ball behind him. As opposed to Connor Colby, who started at right guard and couldn't move anyone. Willis clearly is the second-best guard on the team after Dominick Puni. Backup offensive tackle Austen Pleasants took a few reps at left guard and injured his right knee. He should stay at tackle.

DEFENSIVE LINEMEN: C-PLUS

They didn't sack or hit any of the opposing quarterbacks, but they did shut down the running backs, unlike last week against the Titans or this past Tuesday in the joint practice in El Segundo. Both Romello Height and Sam Okuayoninu made tackles in the backfield, which is promising. Defensive tackle Osa Odighizuwa didn't record any statistics, but he did penetrate the backfield repeatedly and cause havoc. Unfortunately for these guys, they still can't contain a mobile quarterback. They let Trey Freaking Lance run for 42 yards on two carries.

LINEBACKERS: B

Garrett Wallow was outstanding. He played with zero hesitation against the run and made some big solo tackles in the hole. He's the second-best middle linebacker on the team after Fred Warner. Nick Martin also played well against the run, but he's still a bit lost in coverage. As is rookie Jaden Dugger, who gave up an 11-yard completion on a simple check-down right in front of him, then got beaten up the seam by Oronde Gadsden Jr., but the pass was underthrown and incomplete. Teams are going to go after Dugger relentlessly when the regular season starts. I hope he's ready.

DEFENSIVE BACKS: B-PLUS

Deommodore Lenoir didn't give up a catch. Renardo Green gave up one, then left the game with a hamstring injury. His replacement, Jack Jones, broke up two passes without turning his head to find the ball. Rookie Ephesian Prysock broke up a pass over the middle. And second-year cornerback Jacob Robinson nearly intercepted a pass. If Green has to miss a few weeks, I imagine Jones will replace him, but I think Prysock is the better player. And at safety, the 49ers are still waiting for someone to assert himself.

SPECIAL TEAMS: A

Jacob Cowing returned a punt for a touchdown, Nick Martin forced a fumble, which the 49ers recovered, and Eddy Pineiro made two field goals. This group is good. Cowing essentially wrote his ticket to the 53-man roster with the punt return. Good for Jacob. He's a talented young player who has been injured for most of his career.

COACHES: A

Give Kyle Shanahan credit. After getting Kurtis Rourke injured on a risky quarterback draw last week, Shanahan effectively protected both Brock Purdy and Mac Jones tonight. Shanahan also breathed life into his running game and found a couple quality backup running backs in Black and McCormick. Finally, Morris had a fine night shutting down the run. He didn't generate much pressure, but he didn't need to. Overall, the 49ers sent the Chargers a message after getting dominated during the joint practice on Tuesday. Tonight, the 49ers were the bullies.