SANTA CLARA – Here is how the 49ers (4-0) graded in Sunday’s 24-14 win over the Denver Broncos (2-2) at Levi’s Stadium:

PASS OFFENSE: B

Brock Purdy dazzled down the stretch, completing all but one of his final 10 passes for 129 yards and two touchdowns and still without a sack all season. George Kittle’s 54-yard game-clinching touchdown came after an initial block on Nik Bonitto, then a 19.8-mph dash to the goal line with 2:15 remaining. Mike Evans, playing with injured ribs from last Sunday, had a team-high five catches for 76 yards, and all were quite timely. “That’s the most casual 76-yard game I’ve seen. How good is he? Good for us,” Kittle said. Purdy (19-of-30, 218 yards) also sprinkled multiple completions to Christian McCaffrey, Deebo Samuel and Kyle Juszczyk, the last of whom left with a knee injury.

RUN OFFENSE: A-

A 35-carry, 140-yard compilation earned Shanahan’s initial kudos, seeing as how he insisted in Saturday night’s team meeting that they succeed on the ground. Such success came in myriad ways. McCaffrey broke tackles for a 12-yard gain on his second carry, but his longest run (14 yards) set up a 1-yard touchdown run, his third straight game with such a score. Samuel churned out 22- and 20-yard runs. Purdy’s pocket sense led to great escapes, and while he got stopped on a fourth-and-1 sneak early in the game, he converted on third-and-1 before Kittle’s touchdown two plays later. And don’t forget about Kaelon Black’s fourth-and-1 conversion on an unintentional direct snap to the Denver 17, when the score was 3-3.

PASS DEFENSE: B-

No sacks or interceptions. No problem. Not quite. The 49ers’ blitzes come with do-or-die consequences, and some third-down conversions were big gainers, including completions of 10, 25, and 30 yards. Fred Warner was credited for two pass breakups that were nearly forced fumbles. Renardo Green started well. With Upton Stout sidelined by a shoulder injury, Jack Jones got beat by Jaylen Waddle for a touchdown that cut the 49ers’ lead to 17-14 with four minutes to go. Keion White and Sebastian Valdez had the only two hits on Bo Nix (25-of-42, 214 yards).

RUN DEFENSE: B

Dre Greenlaw delivered a game-high 12 tackles with violence and extreme prejudice against a Broncos team that cut him in March. Warner complemented him with seven tackles, while the top five defensive backs also made multiple stops. The 49ers did not make a tackle for loss, but the Broncos did not have a run reach 10 yards, led by J.K. Dobbins’ 40 yards (11 carries) and R.J. Harvey’s 25 yards (seven carries).

SPECIAL TEAMS: A-

Compliments poured in for Siran Neal’s ability to chase down in punt coverage and recover Marvin Mims’ fumble, which replay officials did not nullify and which the 49ers parlayed into their first touchdown drive. Eddy Piñeiro’s 24-yard field goal tied the score at 3, but a 54-yard attempt was easily blocked up the middle by Zach Allen to end the first half. Samuel was fortunate that his fumble on the second-half kickoff landed right in teammate Brayden Willis’ hands.

COACHING: A

No one has coached more 49ers games than Kyle Shanahan. His 167th game vaulted him past Bill Walsh, who of course went 3-0 in the Super Bowl as Shanahan continues to chase his first ring. Purdy credited Shanahan with dialing up the perfect blitz beater for Kittle’s touchdown. Defensive coordinator Raheem Morris’ unit, despite a patchwork front line missing Nick Bosa, has allowed only 64 points all season, third-fewest in the NFL behind the Vikings (51) and the Jaguars (53).