​Niners defensive tackle Gracen Halton (93) strips the ball from Seahawks running back George Holani, a play that resulted in a San Francisco touchdown in the closing seconds of the first half.  (Stephen Brashear/AP Photo/Stephen Brashear)
If you thought the San Francisco 49ers’ first-week win over the Rams down under was the game of the year, beating the Seahawks 32-29 in Seattle just trumped it as the most surprising outcome of the season in a weirdly high-scoring battle defined by brilliant defensive efforts by both teams.Offense: BIn the broad strokes, the Seahawks’ potent defense once again stymied the 49ers, limiting them to 269 total yards. They also recorded the first sack of Brock Purdy on the season. But the offense deserves credit for exploiting the opportunities the defense generally created as far as field position, scoring touchdowns on all three of their red-zone opportunities. But the offense also came up big in the fourth quarter, as Purdy consistently found Mike Evans, including completions for 28 and 23 yards on San Francisco’s last touchdown drive, capped by threading the needle again to Evans on the two-point conversion to give the Niners a 29-26 lead. And the payoff for keeping Christian McCaffrey relatively fresh by using Kaelon Black between the tackles also paid off on the go-ahead possession as CMC generated 28 yards on four touches and Black added 15 on three of his own to reach field-goal range for the decisive kick.Defense: AThe defense won this game with its best effort yet on the year – despite Dre Greenlaw’s ejection – snagging four turnovers, two of which gave the offense the ball on Seattle’s 18- and 11-yard line for instant red-zone opportunities. Rookie Gracen Halton’s touchdown with 13 seconds left in the first half came as his reward for forcing Seahawks reserve back George Holani to fumble in the end zone, while Renardo Green snagged two interceptions against former Niners backup QB Sam Darnold.The Niners had just six sacks in the first four games of the season, on this day they had five, with Jaden Dugger, Sebastian Valdez and Halton recording their first career sacks and Osa Odighizuwa his first sack as a 49er. Fred Warner led with 10 tackles and recorded his third forced fumble on the season.There were moments that Jaxon Smith-Njigba, Seattle’s superb wideout, was able to do damage, such as when he torched Deommodore Lenoir and others for a 38-yard gain and his waltz into the end zone to give Seattle a 23-21 lead in the third quarter, but his failure to haul in Darnold’s throw with a minute left on 3rd-and-10 was an unexpected break.Special teams: DSpecial teams may have delivered the play of the game last week, but this week they were almost responsible for the loss. In the first quarter, Jacob Cowing not calling a fair catch on a punt led to a fumble that gave Seattle the ball at the 24-yard line to set up its first touchdown. Eddy Piñeiro missed a 52-yard field goal wide left on a windless, sunny