By Matt Barrows, Michael-Shawn Dugar and Vic Tafur

Brock Purdy threw a 4-yard touchdown pass to Jake Tonges with 1:34 to go, and Nick Bosa sealed the game with a strip-sack of Sam Darnold, lifting the San Francisco 49ers to a 17-13 victory over the Seahawks on Sunday in Seattle.

The 49ers overcame the loss of George Kittle to injury and some miscues in the kicking game to pull out the victory.

The Seahawks couldn’t get much going on offense, gaining just 230 total yards and scoring only one touchdown, a 1-yard run by Zach Charbonnet. But the defense kept Seattle in it, picking off Purdy twice. The second of those came in the fourth quarter and set up a go-ahead field goal by Jason Myers with 3:24 to go.

Seattle’s special teams also blocked a field goal attempt by Jake Moody, who was just 1-for-3 on the day.

The 49ers dominated the time of possession battle, 37:58-22:02, and outgained the Seahawks 384-230.

Injuries pile up for 49ers

Despite a great deal of turnover this offseason, the 49ers felt confident heading into Week 1 because they still had a roster loaded with stars. In the first half, however, those stars had fallen to the Lumen Field turf.

Fred Warner (kicked in face), Trent Williams (ankle) and Kittle (hamstring) all went into the blue medical tent before halftime. Receiver Jauan Jennings left the game in the fourth quarter with an apparent shoulder injury. Warner and Williams returned to the game. Jennings and Kittle, who caught an opening-drive touchdown pass, did not. Both will have MRIs to determine the extent of their injuries, coach Kyle Shanahan said after the game.

Kittle was quickly declared out for the game, raising doubts about his availability next week in New Orleans and beyond. Furthermore, the 49ers have just three tight ends on the 53-man roster: Kittle, Luke Farrell and Tonges, who filled in for Kittle on Sunday. The team could also promote or elevate Brayden Willis. — Matt Barrows, 49ers beat writer

Robert Saleh’s defense dominates

The 49ers’ defense, in Robert Saleh’s first game back as defensive coordinator, shut down the Seahawks’ running game early and turned to blitzes to rattle Darnold. That kept the 49ers in the game after the early loss of Kittle.

After Purdy threw his second interception near midfield, the 49ers’ defense held the Seahawks to a field goal with 3:24 left.

Sam Okuayinonu earlier forced a fumble, which led to a score-tying field goal early in the fourth quarter. Defensive tackles Kalia Davis and Jordan Elliot each made third-down stops, and linebackers Fred Warner and Dee Winter were all over the field. While rookie cornerback Upton Stout was being bullied early and often, the Seahawks weren’t able to pick on him late. — Vic Tafur, 49ers beat writer

Seahawks fail to make the big plays when it counts

Seattle put itself in position to win the game late, but ultimately, the 49ers’ difference-makers on offense and defense made the clutch plays. Purdy calmly led a 68-yard scoring drive with big-time throws to Ricky Pearsall and Tonges, the latter for the go-ahead score. Cornerback Riq Woolen was on the wrong end of both plays.

When it was Seattle’s time for a rebuttal, newly paid right tackle Abe Lucas was pushed backward by Bosa, causing Darnold to fumble the ball on second-and-5 from the 9-yard line. Bosa also recovered the ball to end the game. That’s what these games come down to: star players delivering when it matters most. San Francisco’s key players were at their best when it was required. Seattle’s were not. — Michael-Shawn Dugar, Seahawks beat writer

Jake Moody makes a play late

Moody didn’t exactly go from goat to hero, but he did make a field goal in the fourth quarter to tie the score after missing his first two. He clanged a 27-yarder off the upright — it still might be shaking — in the second quarter and then had an attempt blocked in the third quarter when the left side of the offensive line collapsed. — Tafur

Christian McCaffrey looks healthy, gains 142 yards

The calf is OK. That was the obvious conclusion after a game in which the 49ers became increasingly reliant on Christian McCaffrey in the running and passing game. The tailback was targeted a team-high 10 times by Purdy and finished with 142 combined yards, his highest total in that category since Week 15 of the 2013 season. McCaffrey seemed to show no ill effects from the calf issue that caused him to come out of Thursday’s practice and miss Friday’s session. The 49ers seemed to work backup Brian Robinson Jr. into the mix more than they did McCaffrey’s top backup in previous seasons. However, Robinson would get only a few snaps before McCaffrey started pestering running backs coach Bobby Turner to enter the game. — Barrows

(Photo: Ricky Pearsall of the 49ers reacts in front of Riq Woolen of the Seahawks on Sunday: Steph Chambers / Getty Images)