The Seahawks (1-1) earned the victory after the Lions (1-1) rallied from a 10-point deficit late in the fourth quarter, extending the game with Riley Patterson's 38-yard field goal as regulation expired.
Smith threw a go-ahead, 3-yard touchdown pass to Lockett early in the fourth and Tre Brown returned a Jared Goff interception for a score on the ensuring drive to give Seattle a 31-21 lead.
Goff showed his resilience after throwing his first interception in 383 attempts — 30 shy of the NFL record — by throwing a 4-yard touchdown pass to Josh Reynolds to cap a drive that started with linebacker Darrell Taylor getting flagged for roughing the passer.
Detroit forced Seattle to punt on the ensuing possession on fourth-and-35, sacking Smith for the first — and only time — when Alex Anzalone tracked him down at his 3.
The Seahawks bounced back from a lopsided loss at home to the Los Angeles Rams with an impressive win against a suddenly relevant team.
The Lions failed to give their fired-up fans a reason to cheer after opening the season with a win on the road against the defending Super Bowl champion Kansas City Chiefs.
Seattle started strong, going 75 yards on 12 plays in nearly 8 minutes with Walker scoring on a 1-yard run.
The Lions answered quickly on Goff's 22-yard touchdown throw to Josh Reynolds. They took a 14-7 lead late in the second quarter when rookie cornerback Devon Witherspoon was fooled on a flea flicker in his NFL debut, allowing Kalif Raymond to get behind him to catch Goff's 36-yard pass.
On Detroit's first snap of the second half, David Montgomery fumbled at the Lions 22 and Seattle took advantage with Walker's 3-yard touchdown run to pull into a tie. As the Lions did early in the game, they responded with a touchdown drive that ended with Montgomery's 4-yard tiebreaking score.
The Seahawks' second 12-play possession ended with Jason Myers, who missed a pair of field goals in the first half, making a 25-yard field goal late in the third quarter.
Seahawks: C Evan Brown (knee) and CB Riq Woolen (chest) were injured during the game and DK Metcalf played with a rib injury.
Lions: Montgomery (thigh) was carted off the field in the fourth quarter. ... OT Taylor Decker (ankle) was inactive, putting Matt Nelson in the starting lineup. ... RG Vaitai Halapoulivaati limped off the field early in the fourth after appearing to hurt his left knee.
Seahawks: Host the Carolina Panthers on Sunday.
Lions: Play the Atlanta Falcons at home Sunday.
AP NFL: https://apnews.com/hub/nfl
Larry Lage, The Associated Press