San Francisco 49ers 31, San Diego Chargers 21

Here are the top-graded players and biggest takeaways from San Francisco’s 31-21 preseason win in San Diego.

Quarterback grades: Christian Ponder, 77.5; QB Colin Kaepernick, 74.9; Jeff Driskel 42.5

Colin Kaepernick proves to be threat on ground

Colin Kaepernick started the game for San Francisco, and was more effective as a runner than a passer. Kaepernick was just two for eight for 25 yards on passes thrown 10+ yards downfield, but added 38 rushing yards (two attempts for 15 yards on option runs and two attempts for 23 yards on scrambles). Rookie Jeff Driskel was the next man up, but was quickly benched after two of his three pass attempts were intercepted. Driskel was replaced by Christian Ponder, who finished with a passer rating of 99.7 with a clean pocket, compared to 59.8 when pressured. Ponder added a pair of rushing touchdowns.

Colin Kaepernick passing under pressure versus Chargers

Top offensive grades

QB Christian Ponder, 77.5

QB Colin Kaepernick, 74.9

TE Je’Ron Hamm, 74.2

WR Jeremy Kerley, 72.7

TE Bruce Miller, 72.5

Rookie LG Joshua Garnett struggles

San Francisco’s offensive line was ineffective throughout the game, and LG Joshua Garnett (40.6) and C Marcus Martin (36.9) were the team’s lowest-graded players on offense. Each player allowed just a pair of hurries in pass protection, but struggled in the run game. LT Colin Kelly earned the team’s best run-blocking grade (91.5), but allowed two hits and four hurries for a team-worst 33.3 pass-blocking grade.

Top defensive grades

LB Shayne Skov, 91.4

CB Rashard Robinson, 86.9

OLB Marcus Rush, 84.8

DE Garrison Smith, 83.6

DE B.J. McBryde, 82.9

Marcus Rush earns top preseason pass-rush grade among all NFL edge defenders

OLB Marcus Rush recorded two sacks, two hurries, and a forced fumble on just 12 pass-rush attempts, and finishes the preseason with the best pass-rush grade of any NFL edge defender. LB Shayne Skov had seven tackles (five defensive stops), and CB Rashard Robinson led the team with a 90.2 coverage grade after allowing two of four passes into his coverage to be caught for 12 yards, and added a pass defense and interception.

Quarterback grades: Kellen Clemens, 65.3; Mike Bercovici, 40.8

Conservative night for backup QB Kellen Clemens

Kellen Clemens was very conservative in this game, attempting just two passes more than 10 yards in the air (both incomplete). Backup Mike Bercovici was slightly more aggressive, completing a 26-yard pass to WR Dominique Williams between the corner and safety against a cover-2 coverage look for the longest Chargers' completion of the game.

Top offensive grades

WR Isaiah Burse, 79.4

C Spencer Pulley, 74.0

TE Asante Cleveland, 68.4

HB Gus Johnson, 66.6

WR Dominique Williams, 66.1

Poor run-blocking leads to limited rushing yardage

San Diego had a tough time moving the ball on the ground. Outside of a Kenneth Farrow 44-yard run, the Chargers gained just 55 yards on 23 attempts, and 54 yards came after contact. Tackle Marcel Jones, guards Vi Teofilo and Kenny Wiggins, center Max Tuerk, and FB Chris Swain all earned negative run-blocking grades, and San Diego running backs forced just three missed tackles on 24 total attempts.

Top defensive grades

S Adrian Phillips, 85.7

NT Ryan Carrethers, 84.1

OLB Chris Landrum, 79.2

LB Jatavis Brown, 79.0

CB Trevor Williams, 78.6

Safety Adrian Phillips earns a clean sheet in coverage

NT Ryan Carrethers concluded a solid preseason by earning a team-best 82.1 run-defense grade, adding three hurries on 21 pass-rush attempts. OLBs Ben Gardner (one sack, one hit, four hurries) and Chris Landrum (three hits, two hurries) were the team’s most productive pass-rushers, and LB James Vaughters added four hurries on just 12 rushes. S Adrian Phillips did not allow any of the three passes into his coverage to be completed, and added a pass defense.

Ready for the Chargers' season opener against the Chiefs? Get the San Diego 2016 season “cheat sheet” here.